Peptidaantigenik disajikan oleh kompleks histokompatibilitas mayor (MHC; atau human leukocyte antigen (HLA)) pada manusia) dan kemudian dikenali oleh limfosit T sitotoksik spesifik-virus (CTL). Oleh karena itu, pemahaman presentasi anti-gen SARS-CoV-2 akan membantu pemahaman kita tentang patogenesis COVID-19. WALTHAM Mass., (BUSINESS WIRE) -- EUROIMMUN, a PerkinElmer, Inc. company (NYSE: PKI), announced today that the U.S. Food and Drug Administration has AntiHIV Western Blood. Deskripsi pemeriksaan: Anti HIV Western Blood RT PCR SARS CoV-2 Kualitatif. Deskripsi pemeriksaan: RT PCR SARS CoV-2 Kualitatif. PCR HIV-1 RNA. Lihat Detail . BCR-ABL. Deskripsi pemeriksaan: BCR-ABL. Lihat Detail . HBV DNA Kuantitatif. Deskripsi pemeriksaan: HBV DNA Kuantitatif. Lihat Detail . HBV DNA Kualitatif Metodeyang digunakan dalam pemeriksaan anti SARS-CoV-2 kuantitatif adalah Electro Chemiluminescence Immunoassay (ECLIA) yang menggunakan protein rekombinan mewakili RBD antigen S, mengukur antibodi spesifik dengan afinitas tinggi terhadap SARS-CoV-2 secara kuantitatif dalam serum pasien dengan satuan U/ml (1 U/ml setara dengan 0.972 AgRDT SARS-CoV-2 1. Ag-RDT SARS-CoV-2 yang memenuhi persyaratan kinerja minimum sensitivitas ≥80% dan spesifi si. tas ≥97% dibandingkan asai referensi NAAT 1 dapat digunakan untuk mendiagnosis infeksi SARS-CoV-2 di situasi-situasi di mana NAAT tidak tersedia atau waktu ketersediaan hasil tidak memberikan manfaat klinis. Vay Tiền Nhanh Ggads. Estimates of SARS-CoV-2 Seroprevalence and Incidence of Primary SARS-CoV-2 Infections Among Blood Donors, by COVID-19 Vaccination Status — United States, April 2021–September 2022 Jefferson M. Jones, MD1; Irene Molina Manrique, MS2; Mars S. Stone, PhD3; Eduard Grebe, PhD3; Paula Saa, PhD4; Clara D. Germanio, PhD3; Bryan R. Spencer, PhD4; Edward Notari, MPH4; Marjorie Bravo, MD3; Marion C. Lanteri, PhD5; Valerie Green, MS5; Melissa Briggs-Hagen, MD1; Melissa M. Coughlin, PhD1; Susan L. Stramer, PhD4; Jean Opsomer, PhD2; Michael P. Busch, MD, PhD3 View author affiliations View suggested citationSummary What is already known about this topic? SARS-CoV-2 hybrid immunity immunity derived from both previous infection and vaccination has been reported to provide better protection than that from infection or vaccination alone. What is added by this report? By the third quarter of 2022, an estimated of persons aged ≥16 years in a longitudinal blood donor cohort had SARS-CoV-2 antibodies from previous infection or vaccination, including from infection alone and from vaccination alone; had hybrid immunity. Hybrid immunity prevalence was lowest among adults aged ≥65 years. What are the implications for public health practice? Low prevalence of infection-induced and hybrid immunity among older adults, who are at increased risk for severe disease if infected, reflects the success of public health infection prevention efforts while also highlighting the importance of this group staying up to date with recommended COVID-19 vaccination, including at least 1 bivalent dose. Altmetric Citations Views Views equals page views plus PDF downloads Changes in testing behaviors and reporting requirements have hampered the ability to estimate the SARS-CoV-2 incidence 1. Hybrid immunity immunity derived from both previous infection and vaccination has been reported to provide better protection than that from infection or vaccination alone 2. To estimate the incidence of infection and the prevalence of infection- or vaccination-induced antibodies or both, data from a nationwide, longitudinal cohort of blood donors were analyzed. During the second quarter of 2021 April–June, an estimated of persons aged ≥16 years had infection- or vaccination-induced SARS-CoV-2 antibodies, including from vaccination alone, from infection alone, and from both. By the third quarter of 2022 July–September, had SARS-CoV-2 antibodies from previous infection or vaccination, including from infection alone and from vaccination alone; had hybrid immunity. Prevalence of hybrid immunity was lowest among persons aged ≥65 years the group with the highest risk for severe disease if infected, and was highest among those aged 16–29 years Low prevalence of infection-induced and hybrid immunity among older adults reflects the success of public health infection prevention efforts while also highlighting the importance of older adults staying up to date with recommended COVID-19 vaccination, including at least 1 bivalent dose.*,† Since July 2020, SARS-CoV-2 seroprevalence in the United States has been estimated by testing blood donations 3. CDC, in collaboration with Vitalant, American Red Cross, Creative Testing Solutions, and Westat, established a nationwide cohort of 142,758 blood donors in July 2021; the cohort included persons who had donated blood two or more times in the preceding year.§ All blood donations collected during April–June 2021 were tested for antibodies against the spike S and nucleocapsid N proteins. Beginning in 2022, up to one blood donation sample per donor was randomly selected each quarter and tested using the Ortho VITROS SARS-CoV-2 Quantitative S immunoglobulin G¶ and total N antibody** tests. Both SARS-CoV-2 infection and COVID-19 vaccination result in production of anti-S antibodies, whereas anti-N antibodies only result from infection. At each donation, blood donors were asked if they had received a COVID-19 vaccine. Using vaccination history and results of antibody testing, the prevalence of the population aged ≥16 years with vaccine-induced, infection-induced, or hybrid immunity was estimated for four 3-month periods April–June 2021, January–March 2022, April–June 2022, and July–September 2022; in addition, the proportion of persons who transitioned from one immune status to another by quarter was estimated. Analysis was limited to 72,748 donors for whom it was possible to ascertain immune status during each period using their prior classification previously infected or vaccinated, antibody testing results, and their vaccination status at the time of each donation.†† The sample data were weighted to account for selection into the study cohort, for nonresponse during the four analysis periods, and for demographic differences between the blood donor population and the overall population. The weights were obtained through a combination of stratification and raking, an iterative weighting adjustment procedure 4. Rates of infection among those previously uninfected were estimated for each period by determining the percentage of anti-N–negative persons seroconverting to anti-N–positive from one 3-month period included in the study to the next. Estimates were stratified by age group 16–29, 30–49, 50–64, and ≥65 years and race and ethnicity§§ Asian, Black or African American [Black], White, Hispanic or Latino [Hispanic], and other. SAS version SAS Institute was used to compute the final weights, and R version R Foundation was used to calculate all the estimates and create the plots.¶¶ Seroprevalence and infection rates were estimated as weighted means and compared by demographic group and vaccination status using two-sided t-tests with a significance level of α = This activity was reviewed by CDC and conducted consistent with applicable federal law and CDC policy.*** During the first quarter examined April–June 2021, an estimated 95% CI = of persons aged ≥16 years had SARS-CoV-2 antibodies from previous infection or vaccination, including 95% CI = from vaccination alone, 95% CI = from infection alone, and 95% CI = from both Figure 1 Supplementary Figure 1, During January–March 2022, 95% CI = of persons aged ≥16 years had antibodies from previous infection or vaccination, including 95% CI = from vaccination alone, 95% CI = from infection alone, and 95% CI = from both. During July–September 2022, 95% CI = of persons had antibodies from previous infection or vaccination, including 95% CI = with vaccine-induced immunity alone, 95% CI = with infection-induced immunity alone, and 95% CI = with hybrid immunity. During July–September 2022, the prevalence of infection-induced immunity was 95% CI = among unvaccinated persons and 95% CI = among vaccinated persons. During July–September 2022, the lowest prevalence of hybrid immunity, 95% CI = was observed in persons aged ≥65 years, and the highest, 95% CI = in adolescents and young adults aged 16–29 years Figure 2 Supplementary Figure 2, During all periods, higher prevalences of hybrid immunity were observed among Black and Hispanic populations than among White and Asian populations Supplementary Figure 3, Among persons with no previous infection, the incidence of first infections during the study period conversion from anti-N–negative to anti-N–positive was higher among unvaccinated persons Table. From April–June 2021 through January–March 2022, the incidence of first SARS-CoV-2 infections among unvaccinated persons was compared with among vaccinated persons p< From January–March 2022 through April–June 2022, the incidence among unvaccinated persons was and was among vaccinated persons. Between April–June 2022 and July–September 2022, the incidence among unvaccinated persons was compared with among vaccinated persons p< Incidence of first SARS-CoV-2 infections was higher among younger than among older persons and was lower among Asian persons than among other racial and ethnic populations, but the differences among groups narrowed over time. Discussion Both infection-induced and hybrid immunity increased during the study period. By the third quarter of 2022, approximately two thirds of persons aged ≥16 years had been infected with SARS-CoV-2 and one half of all persons had hybrid immunity. Compared with vaccine effectiveness against any infection and against severe disease or hospitalization, the effectiveness of hybrid immunity against these outcomes has been shown to be higher and wane more slowly 2. This increase in seroprevalence, including hybrid immunity, is likely contributing to lower rates of severe disease and death from COVID-19 in 2022–2023 than during the early pandemic.††† The prevalence of hybrid immunity is lowest in adults aged ≥65 years, likely due to higher vaccination coverage and earlier availability of COVID-19 vaccines for this age group, as well as to higher prevalences of behavioral practices to avoid infection 5. However, lower prevalences of infection-induced and hybrid immunity could further increase the risk for severe disease in this group, highlighting the importance for adults aged ≥65 years to stay up to date with COVID-19 vaccination and have easy access to antiviral medications. COVID-19 vaccine efficacy studies have reported reduced effectiveness against SARS-CoV-2 infection during the Omicron-predominant period compared with earlier periods and have shown that protection against infection wanes more rapidly than does protection against severe disease 6,7. In this study, unvaccinated persons had higher rates of infection as evidenced by N antibody seroconversion than did vaccinated persons, indicating that vaccination provides some protection against infection. The differences in incidence could also be due to systematic differences between vaccinated and unvaccinated persons in terms of the prevalence of practicing prevention behaviors such as masking and physical distancing. The relative difference in infection rates narrowed during the most recent months, possibly because of waning of vaccine-induced protection against infection in the setting of increased time after vaccination or immune evasion by the SARS-CoV-2 Omicron variant. The narrowing of difference in infection rates might also be attributable to increasing similarities in behavior among vaccinated and unvaccinated persons during late 2022 8. The findings in this report are subject to at least six limitations. First, although COVID-19 booster vaccine doses and reinfections can strengthen immunity 9,10, this analysis did not account for these effects because blood donor vaccination history did not include the number of doses received, and data on reinfections were not captured. Second, immunity wanes over time, but time since vaccination or infection was not included in the analysis 2. Third, vaccination status was self-reported, potentially leading to misclassification. Fourth, although the results were adjusted based on differences in blood donor and general population demographics, estimates from blood donors might not be representative of the general population; thus, these results might not be generalizable. Fifth, vaccinated and unvaccinated persons might differ in other ways not captured by this analysis 8, nor can causality be inferred from the results on relative infection incidence. Finally, if both vaccination and infection occurred between blood donations included in the study, the order of occurrence could not be determined, and some unvaccinated donors might have been vaccinated before infection and thus misclassified; in 2022, this was uncommon and occurred in < of donors during any 3-month period. This report found that the incidence of first-time SARS-CoV-2 infection was lower among persons who had received COVID-19 vaccine than among unvaccinated persons and that infection-induced and hybrid immunity have increased but remain lowest in adults aged ≥65 years. These adults have consistently had a higher risk for severe disease compared with younger age groups, underscoring the importance of older adults staying up to date with recommended COVID-19 vaccination, including at least 1 bivalent dose. Acknowledgments Brad Biggerstaff, Matthew McCullough, CDC; Roberta Bruhn, Brian Custer, Xu Deng, Zhanna Kaidarova, Kathleen Kelly, Anh Nguyen, Graham Simmons, Hasan Sulaeman, Elaine Yu, Karla Zurita-Gutierrez, Vitalant Research Institute; Akintunde Akinseye, Jewel Bernard-Hunte, Robyn Ferg, Rebecca Fink, Caitlyn Floyd, Isaac Lartey, Sunitha Mathews, David Wright, Westat; Jamel Groves, James Haynes, David Krysztof, American Red Cross; Ralph Vassallo, Vitalant; Sherri Cyrus, Phillip Williamson, Creative Testing Solutions; Paul Contestable, QuidelOrtho; Steve Kleinman, University of British Columbia; CDC, Vitalant Research Institute, Westat, American Red Cross, and Creative Testing Solutions staff members; blood donors whose samples were analyzed and who responded to surveys for this study. Corresponding author Jefferson M. Jones, ioe8 Center for Immunization and Respiratory Diseases, CDC; 2Westat, Rockville, Maryland; 3Vitalant Research Institute, San Francisco, California; 4American Red Cross, Washington, DC; 5Creative Testing Solutions, Tempe, authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. No potential conflicts of interest were disclosed. * † § Blood donors who donated at least twice during the year before July 2021 were included in the cohort, because they might represent persons who were more likely to donate frequently. Among donors who donated more than once during a quarter, one sample was selected at random for testing. ¶ ** †† §§ Persons of Hispanic origin might be of any race but are categorized as Hispanic; all racial groups are non-Hispanic. ¶¶ Jackknife replication was used to compute replicate weights. Weights were adjusted for nonresponse using adjustment cells created by age category, vaccination and previous infection status, and blood collection organization Vitalant or American Red Cross. Raking was used to further adjust the weights to account for demographic differences between the blood donor population and population. The demographic variables used for raking were sex female and male, age group 16–24, 25–34, 35–44, 45–54, 55–64, and ≥65 years, and race and ethnicity Asian, Black, White, Hispanic, and other. *** 45 part 46, 21 part 56; 42 Sect. 241d; 5 Sect. 552a; 44 Sect. 3501 et seq. ††† Accessed May 25, 2023. References Rader B, Gertz A, Iuliano AD, et al. Use of at-home COVID-19 tests—United States, August 23, 2021–March 12, 2022. MMWR Morb Mortal Wkly Rep 2022;71489–94. PMID35358168 Bobrovitz N, Ware H, Ma X, et al. Protective effectiveness of previous SARS-CoV-2 infection and hybrid immunity against the Omicron variant and severe disease a systematic review and meta-regression. Lancet Infect Dis 2023;23556–67. PMID36681084 Jones JM, Stone M, Sulaeman H, et al. Estimated US infection- and vaccine-induced SARS-CoV-2 seroprevalence based on blood donations, July 2020–May 2021. JAMA 2021;3261400–9. PMID34473201 Deville J-C, Särndal C-E, Sautory O. Generalized raking procedures in survey sampling. J Am Stat Assoc 1993;881013–20. Steele MK, Couture A, Reed C, et al. Estimated number of COVID-19 infections, hospitalizations, and deaths prevented among vaccinated persons in the US, December 2020 to September 2021. JAMA Netw Open 2022;5e2220385. PMID35793085 Higdon MM, Wahl B, Jones CB, et al. A systematic review of coronavirus disease 2019 vaccine efficacy and effectiveness against severe acute respiratory syndrome coronavirus 2 infection and disease. Open Forum Infect Dis 2022;9ofac138. PMID35611346 Feikin DR, Higdon MM, Abu-Raddad LJ, et al. Duration of effectiveness of vaccines against SARS-CoV-2 infection and COVID-19 disease results of a systematic review and meta-regression. Lancet 2022;399924–44. PMID35202601 Thorpe A, Fagerlin A, Drews FA, Shoemaker H, Scherer LD. Self-reported health behaviors and risk perceptions following the COVID-19 vaccination rollout in the USA an online survey study. Public Health 2022;20868–71. PMID35717747 Sette A, Crotty S. Immunological memory to SARS-CoV-2 infection and COVID-19 vaccines. Immunol Rev 2022;31027–46. PMID35733376 Atti A, Insalata F, Carr EJ, et al.; SIREN Study Group and the Crick COVID Immunity Pipeline Consortium. Antibody correlates of protection from SARS-CoV-2 reinfection prior to vaccination a nested case-control within the SIREN study. J Infect 2022;85545–56. PMID36089104 FIGURE 1. Prevalences of vaccine-induced, infection-induced, and hybrid* immunity† against SARS-CoV-2 among blood donors aged ≥16 years — United States, April 2021–September 2022 * Immunity derived from a combination of vaccination and infection. † Ascertained by the presence of anti-spike antibodies present in both COVID-19–vaccinated and SARS-CoV-2–infected persons and anti-nucleocapsid antibodies present only in previously infected persons and self-reported history of vaccination. FIGURE 2. Prevalences of vaccine-induced, infection-induced, and hybrid* immunity† against SARS-CoV-2 among blood donors aged ≥16 years, by age group — United States, April 2021–September 2022 * Immunity derived from a combination of vaccination and infection. † Ascertained by the presence of anti-spike antibodies present in both COVID-19–vaccinated and SARS-CoV-2–infected persons and anti-nucleocapsid antibodies present only in previously infected persons and self-reported history of vaccination. TABLE. Estimated percentage* of persons infected with SARS-CoV-2 for the first time among blood donors, by analysis quarter, sociodemographic characteristics, and vaccination status — United States, April 2021–September 2022 Characteristic Period, % 95% CI Apr–Jun 2021 to Jan–Mar 2022 Jan–Mar 2022 to Apr–Jun 2022 Apr–Jun 2022 to Jul–Sep 2022 Overall Total Unvaccinated Vaccinated Age group, yrs 16–29 Total Unvaccinated Vaccinated 30–49 Total Unvaccinated Vaccinated 50–64 Total Unvaccinated Vaccinated ≥65 Total Unvaccinated Vaccinated Race and ethnicity§ Asian Total Unvaccinated Vaccinated Black or African American Total Unvaccinated Vaccinated White Total Unvaccinated Vaccinated Hispanic or Latino Total Unvaccinated Vaccinated Other and multiple races¶ Total Unvaccinated Vaccinated * Percentage of uninfected persons anti-nucleocapsid–negative in the previous 3-month period seroconverting to anti-nucleocapsid–positive. If both vaccination and infection occurred between donations included in the study, the order could not be determined, and some unvaccinated donors might have been vaccinated before infection and thus misclassified. † If donors who transitioned from no antibodies to hybrid immunity between April–June 2021 and January–March 2022 were excluded, an estimated 95% CI = of unvaccinated donors were infected. For other periods, exclusion did not substantially change results. Between January–March and April–June 2022, of persons shifted from no antibodies to hybrid immunity. Between April–June and July–September 2022, of persons shifted from no antibodies to hybrid immunity. § Persons of Hispanic or Latino Hispanic origin might be of any race but are categorized as Hispanic; all racial groups are non-Hispanic. ¶ Includes American Indian or Alaska Native and non-Hispanic persons of other races. Suggested citation for this article Jones JM, Manrique IM, Stone MS, et al. Estimates of SARS-CoV-2 Seroprevalence and Incidence of Primary SARS-CoV-2 Infections Among Blood Donors, by COVID-19 Vaccination Status — United States, April 2021–September 2022. MMWR Morb Mortal Wkly Rep 2023;72601–605. DOI MMWR and Morbidity and Mortality Weekly Report are service marks of the Department of Health and Human Services. Use of trade names and commercial sources is for identification only and does not imply endorsement by the Department of Health and Human Services. References to non-CDC sites on the Internet are provided as a service to MMWR readers and do not constitute or imply endorsement of these organizations or their programs by CDC or the Department of Health and Human Services. CDC is not responsible for the content of pages found at these sites. URL addresses listed in MMWR were current as of the date of publication. All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version and/or the original MMWR paper copy for printable versions of official text, figures, and tables. Questions or messages regarding errors in formatting should be addressed to mmwrq Petugas memeriksa beberapa sampel PCR COVID-19 ilustrasi. JAKARTA - Pendistribusian vaksin SARS-CoV-2 alias Covid-19 tengah berlangsung. Di tengah kondisi itu, banyak pertanyaan bermunculan terkait seberapa besar kekebalan tubuh seseorang yang pernah terpapar Covid-19. Menurut Muhammad Irhamsyah, dokter spesialis patologi di Klinik Primaya Hospital Bekasi Barat dan Bekasi Timur, ada metode untuk memeriksanya. Kekebalan tubuh terhadap Covid-19 bisa diketahui melalui tes antibodi SARS-CoV-2 kuantitatif. "Pemeriksaan ini dapat dilakukan pada orang-orang yang pernah terinfeksi Covid-19, orang yang sudah mendapatkan vaksinasi, serta dapat digunakan untuk mengukur antibodi pada donor plasma konvalesen yang akan ditransfusikan," ujar Irhamsyah. Tes mendeteksi protein yang disebut antibodi, khususnya antibodi spesifik terhadap SARS-CoV-2. Prinsipnya menggunakan pemeriksaan laboratorium imunoserologi pada sebuah alat automatik autoanalyzer untuk mendeteksi antibodi itu. Pemeriksaan ini biasa disebut dengan ECLIA Electro chemiluminescence immunoassay. ECLIA mendeteksi, mengikat, serta mengukur antibodi netralisasi, yaitu antibodi yang berikatan spesifik pada struktur protein Spike SARS-CoV-2. Protein itu terdapat pada permukaan virus Covid-19 sebelum memasuki sel-sel pada tubuh. Pengukuran menggunakan label-label yang berikatan spesifik dengan antibodi netralisasi. Jenis sampel yang digunakan yakni sampel serum dan plasma. BACA JUGA Ikuti News Analysis News Analysis Isu-Isu Terkini Perspektif Klik di Sini Loading metrics Open Access Peer-reviewed Research Article Michael Tu, Jordan Cheng, Fang Wei, Feng Li, David Chia, Omai Garner, Sukantha Chandrasekaran, Richard Bender, Charles M. Strom , David T. W. Wong Development and validation of a quantitative, non-invasive, highly sensitive and specific, electrochemical assay for anti-SARS-CoV-2 IgG antibodies in saliva Samantha H. Chiang, Michael Tu, Jordan Cheng, Fang Wei, Feng Li, David Chia, Omai Garner, Sukantha Chandrasekaran, Richard Bender, Charles M. Strom x Published July 1, 2021 Figures AbstractAmperial™ is a novel assay platform that uses immobilized antigen in a conducting polymer gel followed by detection via electrochemical measurement of oxidation-reduction reaction between H2O2/Tetrametylbenzidine and peroxidase enzyme in a completed assay complex. A highly specific and sensitive assay was developed to quantify levels of IgG antibodies to SARS-CoV-2 in saliva. After establishing linearity and limit of detection we established a reference range of 5 standard deviations above the mean. There were no false positives in 667 consecutive saliva samples obtained prior to 2019. Saliva was obtained from 34 patients who had recovered from documented COVID-19 or had documented positive serologies. All of the patients with symptoms severe enough to seek medical attention had positive antibody tests and 88% overall had positive results. We obtained blinded paired saliva and plasma samples from 14 individuals. The plasma was analyzed using an EUA-FDA cleared ELISA kit and the saliva was analyzed by our Amperial™ assay. All 5 samples with negative plasma titers were negative in saliva testing. Eight of the 9 positive plasma samples were positive in saliva and 1 had borderline results. A CLIA validation was performed as a laboratory developed test in a high complexity laboratory. A quantitative non-invasive saliva based SARS-CoV-2 antibody test was developed and validated with sufficient specificity to be useful for population-based monitoring and monitoring of individuals following vaccination. Citation Chiang SH, Tu M, Cheng J, Wei F, Li F, Chia D, et al. 2021 Development and validation of a quantitative, non-invasive, highly sensitive and specific, electrochemical assay for anti-SARS-CoV-2 IgG antibodies in saliva. PLoS ONE 167 e0251342. Chandrabose Selvaraj, Alagappa University, INDIAReceived January 14, 2021; Accepted April 25, 2021; Published July 1, 2021Copyright © 2021 Chiang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are Availability Data is available on figshare DW is supported by U54HL119893, UCLA Keck Foundation Research Award Program. SC is supported by F30DE027615. This study was partially funded by Liquid Diagnostics, LLC LD. The funder provided reimbursement to MT as a paid consultant. This author contributed to this study by performing some experiments and in manuscript preparation. He did not contribute to the decision to publish, data collection or interests CS in an unpaid CEO of LD. CS, MT, RB, and DW are equity holders in LD. LD is the exclusive license holder for the Amperial™ technology from the University of California and hopes to commercialize products based on this technology. This does not alter our adherence to PLOS ONE policies on sharing data an materials. IntroductionA novel corona virus, severe acute respiratory syndrome coronavirus 2 SARS-CoV-2, has caused a global pandemic causing major disruptions world-wide [1]. Multiple high-throughput PCR based tests have been developed that are reasonably sensitive and specific, however the same cannot be said for antibody testing, prompting The Center for Disease Control CDC to issue guidelines entitled “Interim Guidelines for COVID-19 Antibody Testing” [2]. This publication describes the variability of in-home antibody tests and the lack of specificity required to make home-based antibody testing a valuable tool for epidemiologic surveillance. Having a reliable self-collection antibody test may be of enormous help in epidemiologic studies of background immunity, testing symptomatic individuals without RNA based testing during their acute illness, and screening health care providers and first responders to establish prior COVID-19 infection. Such a test may also be valuable in following vaccinated patients to assess the kinetics of anti-SARS-CoV-2 antibody production following inoculation. Multiple serological tests based on serum or plasma have been developed and marketed, with ELISA and lateral flow methods predominating. However, many methods suffer from low sensitivities and specificities [2–6]. Antibodies begin appearing in the first week following the development of symptoms. IgG, IgM, and IgA are detectable with IgA appearing somewhat earlier than IgG and IgM. Most patients seroconvert by 2 weeks following symptoms. Unlike IgA and IgM, IgG persists for several months following infection [7–9]. In a published study of 1,797 Icelandic individuals recovered from qPCR documented COVID-19 disease, 91% were IgG seropositive and antibody levels remained stable for 4 months after initial symptoms [10]. Notably of individuals quarantined due to exposure but untested for virus, with negative qPCR results, tested positive for IgG antibodies. Of 18,609 patients who were both unexposed and asymptomatic, the seropositivity rate was [11]. Since health care systems are burdened with care for COVID-19 patients, having a test that does not require phlebotomy would be extremely beneficial. To that end, investigations have been carried out using home finger prick blood sampling and even some home blood spot testing lateral flow strips [5–7]. However, home finger stick is invasive and not acceptable to some individuals, and requires a health care professional to administer the test to vulnerable individuals such as the elderly and children. In addition, home blood collection tests are less accurate than phlebotomy, with specificities less than 98%. In a low prevalence disease, the positive predictive value for a test with 98% specificity is less than 50% [7, 11]. Saliva is an oral fluid that is obtained easily and non-invasively. Proteomic studies show that the immunoglobulin profile in saliva is nearly identical to that of plasma [12]. Therefore, saliva is an excellent medium for COVID-19 antibody measurement. There are several commercially available collection devices to facilitate saliva collection, stabilization of IgG, and transport. A recently published study demonstrated excellent correlation between levels of COVID-19 antibodies in serum and saliva [13]. In order to be useful in population-based screening and to determine individual immunity in exposed populations, a SARS-CoV-2 antibody test must be highly specific because of the low seroprevalence rate in the population [2, 14]. In addition, the ability to quantify antibody levels is important for vaccine development and in monitoring for waning immunity [2, 14]. The only published saliva based assay for SARS-CoV-2 antibodies had only 89% sensitivity with 98% specificity [13], leading to a positive predictive value of only 49% in a population with a 2% prevalence of COVID-19 exposure. Our goal was to develop a non-invasive saliva based quantitative test for COVID-19 antibodies with exquisite sensitivity. We reviewed existing literature to find the SARS-CoV-2 antigen domain with the highest specificity and the ability to distinguish between the COVID-19 virus and other related Coronaviruses. The S1 domain is the most specific in terms of cross reactivity with other Corona and other respiratory viruses. As recombinant S1 antigen is readily available from at least 2 vendors, we chose the S1 antigen for our assay development. Levels of IgM and IgA deteriorate rapidly following recovery from COVID-19 infection; IgG levels remain detectable for several weeks to months [10]. Since the intended use of our assay is for population-based screening and vaccine efficacy monitoring, we chose to assay IgG only. The Amperial™ technology, formerly known as Electric Field Induced Release and Measurement EFIRM™, is a novel platform capable of performing quantitation of target molecules in both blood and saliva [15]. The device works by immobilizing capture moieties on the surface of an electrode structure for capturing target analytes and then quantifying the target analyte through electrochemically measuring oxidation-reduction between a hydrogen peroxide and tetramethylbenzidine substrate and peroxidase enzyme in a completed assay sandwich. The assay takes place on electrodes packaged in the format of a traditional 96-well microtiter plate, making the assay technique highly compatible and scalable with existing lab liquid handling instruments. We developed quantitative Amperial™ assays for IgG, IgM, and IgA antibodies to the S1 spike protein antigen of SARS-CoV-2. This test is highly sensitive >88% and specific > for patients with COVID-19 infections and correlates well with plasma ELISA analysis. The unique assay described in this article is completely non-invasive, allows home-collection, is quantitative, and has shown no false positives in 667 unexposed individuals, leading to a specificity of at least The assay has strong utility for clinical laboratories as it does not require purification/extraction of the saliva specimen, but the sample can simply be pipetted out of the collection device, diluted, and pipetted to the assay plate. The turnaround time of the assay is also fast, requiring less than 1 hour for a complete assay to be run. The widespread use of this test may be of great value in identifying individuals with prior exposure to SARS-CoV-2, to follow patients longitudinally to determine the kinetics of diminishing antibody concentration, and may be of special value in the longitudinal monitoring of vaccinated individuals to assess continued serologic immunity. Materials and methodsThe schematic of the Amperial™ SARS-CoV-2 IgG antibody is shown in Fig 1. The principle of the Amperial™ platform is that a biomolecule in this case SARS-CoV-2 Spike protein S1 antigen is added to a liquid pyrrole solution that is then pipetted into the bottom of microtiter wells containing a gold electrode at the bottom of each well. After the solution is added to each well, the plate is placed into the Amperial™ Reader and subjected to an electric current leading to polymerization. This procedure results in each well becoming coated with a conducting polymer gel containing the S1 antigen. Following the polymerization, diluted saliva, plasma, or serum is added to the well. Specific anti-S1 antibodies bind to the S1 antigen in the polymer. After rigorous washing procedures, the bound antibody is detected by using biotinylated anti-human IgG and then the signal is amplified by a standard streptavidin / horseradish peroxidase reaction that produces an electric current measured by the Amperial™ Reader in the nanoampere nA scale. The instrument is capable of accurately measuring current in the picoampere pA range, so the measurement is well within the ability of the instrument [13, 14, 16, 17]. The measurement of current rather than optical absorbance, as is done in the typical ELISA, has two important advantages over standard ELISA. Firstly, it allows precise quantitation of the amount of bound antibody and secondly, the measurement of current rather than optical absorbance allows increased sensitivity. Since antibody levels in saliva are lower than in plasma [13, 16], this increased sensitivity is crucial. The precise details of the assay are described in the next paragraph. COVID-19 Spike-1 Antigen Sanyou-Bio, Shanghai, China was diluted to a concentration of μg / mL, added to each well of the microtiter plate, and co-polymerized with pyrrole Sigma-Aldrich, St. Louis, MO onto the bare gold electrodes by applying a cyclic square wave electric field at 350 mV for 1 second and 1100 mV for 1 second. In total, polymerization proceeded for 4 cycles of 2 seconds each. Following this electro-polymerization procedure, 6 wash cycles were performed using 1x PBS with Tween-20 PBS-T using a 96-channel Biotek 405LS plate washer programmed to aspirate and dispense 400 μL of solution per cycle. Following the application of the polymer layer, 30 μL of saliva diluted at a 110 ratio in Casein/PBS Thermo-Fisher, Waltham, MA was pipetted into each well and incubated for 10 minutes at room temperature. Unbound components were removed by performing 6 wash cycles of PBS-T using the plate washer. Biotinylated anti-human IgG secondary antibody Thermofisher, Waltham, MA at a stock concentration of mg / mL was diluted 1500 in Casein/PBS and 30 μL pipetted to the surface of each well and incubated for 10 minutes at room temperature followed by 6 wash cycles using PBS-T. Subsequently, 30 μL of Poly-HRP80 Fitzgerald Industries, Acton, MA at a stock concentration of 2 μg / mL was diluted 125 in Casein/PBS, added to the wells, and incubated at 10 minutes at room temperature. Following a final wash using 6 cycles of PBS-T, current generation is accomplished by pipetting 60 μL of 1-Step Ultra TMB Thermofisher, Waltham, MA to the surface of the electrode and placing the plate into the Amperial™ reader where current is measured at -200 mV for 60 seconds. The current in nA is measured 3 times for each well. The process for reading the entire 96 well plate requires approximately 3 minutes. Plasma quantitative Amperial™ assay for SARS-CoV-2 IgG The protocol is similar to the Amperial™ SARS-CoV-2 IgG antibody for saliva samples. Following the application of the polymer layer, 30 μL of plasma diluted at a 1100 ratio in Casein/PBS Thermo-Fisher, Waltham, MA was pipetted into each well and incubated for 10 minutes at room temperature. The standard curve for plasma contains the following points 300 ng / ml, 150 ng / ml, 75 ng / ml, ng / ml, ng / ml, and 0 ng / ml. Plasma SARS-CoV-2 ELISA assay We purchased FDA EUA ELISA kits EUROIMMUN Anti-SARS-CoV-2 ELISA Assay for detection of IgG antibodies EUROIMMUN US, Mountain Lakes, NJ, Product ID EI 2606–9601 G, Lot E2001513BK. We processed samples exactly as described in the package insert. Human subjects Volunteers, with prior positive qPCR tests for COVID-19 infection or positive antibody tests using currently available FDA EUA-cleared antibody tests were consented via a written consent. Subjects enrolled were all over the age of 18. Subject participants responded to a questionnaire regarding severity of symptoms, onset of symptoms, and method of diagnosis UCLA IRB 06-05-042. Severity of symptoms were self-graded on the following 7-point scale 0 Asymptomatic 1 Mild Barely noticed, perhaps slight fever and cough 2 Moderate felt moderately ill but did not need to seek medical care 3 Sought medical Care but was not admitted to hospital 4 Hospitalized 5 Admitted to ICU 6 Placed on Ventilator A set of 13 paired saliva and plasma samples were provided by the Orasure™ Company. Saliva collection All COVID-19 samples were obtained using the Orasure™ FDA-cleared saliva collection device and used according to manufacturer instructions. The Orasure™ collection device consists of an absorbent pad on the end of a scored plastic wand. The individual places the pad between cheek and gum for a period of 2–5 minutes. Subsequently the wand and pad are placed into a tube containing transport medium, the top of the stick is broken off, and the tube is sealed for transport. The sealed tube is placed into a zip-lock bag and shipped by any standard method. According to the package insert, samples are stable at ambient temperature for 21 days see results below and Orasure™ website. An alternate sample collection method involves the individual swabbing the pad 4 times in the gingival tooth junction prior to placing the pad between the cheek and gum. This method has been shown to improve IgG yield in some patients with low antibody levels personal communication with Orasure Technologies, Inc.. Participant recruitment method Positive samples determined either through a positive SARS-CoV-2 viral test or antibody test were acquired beginning May 2020 to July 2020 via the described Orasure™ Oral Fluid Collection Device Kit previous described. Subjects were recruited into the study via electronic correspondence during the early stages of the COVID-19 pandemic in regions affected by COVID-19 California, Illinois, New York, New Jersey. Subjects are all over the age of 18. Subjects are not representative of the general population. Samples collected pre-2012 were used as controls. Saliva was collected from healthy individual volunteers at meetings of the American Dental Association between 2006 and 2011. Consent was obtained under IRB approval UCLA IRB 06-05-042. Both male and females, mostly non-smokers, 18–80 years of age, and differing ethnicities were included. All subjects were consented prior to collection. Each subject expectorated ~ 5 mL of whole saliva in a 50cc conical tube set on ice. The saliva was processed within 1/2 hour of collection. Samples were spun in a refrigerated centrifuge at 2600 X g for 15 minutes at 4°C. The supernatant cell-free saliva was then pipetted into two-2 mL cryotubes and μL Superase-In Ambion, Austin, TX was added as a preservative. Each tube was inverted to mix. The samples were frozen in dry ice and later stored in -80°C. Sample size and statistical methods Due to the nature of the pandemic and the evolving nature of EUA diagnostics during the early phases of the pandemic, no power calculations were performed for study size but instead the FDA/EUA recommendation of 30 subjects was followed. For components of work that required comparisons between groups, student’s T-test was conducted. p value, corresponds to a 95% confidence or p value, corresponds to 99% confidence. Data analysis performed was using GraphPad Prism Results Linearity Fig 2 demonstrates the dynamic range and linearity of the assay. In these experiments varying amounts of monoclonal human anti-S1 IgG was added to a saliva sample from a healthy volunteer and subjected to the assay. Fig 2 shows a range of to 6 ng/ml. The Y-axis shows nano-amperage measured nA. The X-axis represents spike-in concentrations of IgG. The assay begins to become saturated at about 3 ng / ml. Fig 3 shows dilutions down to ng / ml to ng / ml and shows linearity in that range. This allows us to create a standard curve containing the following points 3 ng / ml, ng / ml, ng / ml, ng / ml, ng / ml, and 0 ng / ml. Fig 2. Dynamic range and linear range of Amperial™ anti-Spike S1 IgG Amount of spike in anti-SARS-CoV-2 IgG in ng / ml. Y-axis Normalized current in nA. Panel A 0–5 ng / ml Panel B ng / ml. Inhibition assay In order to demonstrate the specificity for the assay on actual clinical samples, we used the saliva from 3 recovered patients who had high levels of SARS-CoV-2 antibodies and added exogenous S1 antigen in varying amounts prior to analysis on the Amperial™ assay. The exogenous S1 antigen should compete for binding sites and therefore extinguish the nA signal. Fig 3 shows the results of this experiment. The red, purple, and green represent 3 different patients. The X-axis demonstrates increasing concentration of exogenous S1 added to the saliva before subjecting it to the assay. As shown, saliva pre-incubated with S1 antigen extinguishes the detectable IgG signal proportionately, therefore demonstrating the specificity of the assay to S1 antigen in clinical samples. Matrix effects Since we are be comparing samples collected by various methods, it is vital to determine if any significant matrix effects could interfere with data interpretation. We examined the 3 different collection methods used in this study Expectoration/centrifugation, Orasure™ without swabbing and Orasure™ with swabbing. Two methods of collection using the Orasure™ Oral Fluid Collection Device were tested. The first method non-swabbing collects saliva by placing an absorbent pad into the lower gum area for 2–5 minutes and then placing the saturated collection pad into a preservative collection tube. The second method swabbing adds the step of first gently rubbing the collection pad along gum line, between the gum and cheek, 5 times, before placing the device in the lower gum area for 2–5 minutes, and then immersing the saturated collection pad into the collection tube. Healthy donors n = 5 collected their saliva using these two different methods. The control pre-2012 samples were collected with an expectoration protocol for whole saliva collection falcon tubes, processing centrifuge, stabilization, and storage. Five samples collected by each of the 3 methods and were analyzed in duplicate. The results are shown in Fig 4 under the heading “No spike in.” There are no differences among 3 sample types. We then added monoclonal human anti-S1 IgG to each sample and again ran them in duplicate Fig 4 above caption Spike-in ng / ml IgG. A non-parametric Student t-test was performed with no significant differences between any of the collection methods. Stability The Orasure™ collector is an FDA-cleared device for the analysis of anti-HIV IgG. The package insert describes a 21-day stability at ambient temperature. We wished to establish the stability of anti-COVID-19 IgG using this collector. Passive whole saliva was collected from four healthy individuals using 50 mL falcon tubes and spiked with anti-Spike S1 IgG to reach a final concentration of 300 ng / ml. Aliquots of mL of saliva were placed into 50 mL tubes and then the sponge of the Orasure™ collector was submerged into the saliva for five minutes and processed as described in Methods. The collected saliva was then aliquoted into PCR tubes and left at ambient temperature 21°C for 0, 1, 3, 7, and 14 days before storage at -80°C. After 14 days, samples were thawed and assayed using the anti-Spike S1 IgG Amperial™ assay to assess stability. At 14 days, 95% of the original signal remained, demonstrating the 14-day stability of anti-SARS-CoV-2 antibodies collected in Orasure™ containers see Fig 5. Fig 5. Stability study performed on spike-in of SARS-CoV-2 IgG into healthy saliva specimen using two different methods a research SOP which involves expectoration into a falcon tube and the Orasure™ Oral Fluid collection device.The collect saliva was aliquoted and left at ambient temp for 0, 1, 3, 7, 14 days. Results were normalized relative to the measured assay signal of a sample at day 0. Results show that the sample is stable with no significant degradation for up to 14 days. Specificity and reference range Once we established no significant differences between the tube collection method and the Orasure™ collector method, we analyzed a series of 667 samples collected between 2006 and 2009 at the annual meeting of the American Dental Association. Scatter plots of these data for both nA and ng / ml are shown in Fig 6A and 6B. We established the mean and standard deviation for both raw nA values and concentration in ng / ml. In order to maximize specificity, we selected a reference range > 5 SD above the mean. A 5 sigma level would lead to a specificity of In fact, we have never seen a healthy sample above the 5 sigma level. As will be seen, the sensitivity of the assay remains greater than 88% even with this rigorous specificity. Fig 6. Healthy reference range of Amperial™ saliva anti-SARS-CoV-2 IgG assay of 667 unexposed subjects in A normalized current ΔnA with mean = and cutoff = and B concentration ng / ml with mean = and cutoff = Recovered COVID-19 patients Fig 7 displays the scatter plot for 667 healthy controls and 34 volunteer patients who recovered from COVID-19 infection. All patients were a minimum of 14 days post onset of symptoms and some patients were as many as 15 weeks post symptoms. The 5 sigma cutoff is shown by the green dotted line. A more detailed discussion of the recovered patients appears in the following section. The data show that all healthy patients are negative and 30 of the 34 recovered patients are positive. These data demonstrate a sensitivity of 88% and a specificity of > It is important to note that not all recovered patients have detectable antibody [10] so the 4 patients with undetectable antibody may be biologically negative and not the result of lack of sensitivity of the assay. Fig 8 demonstrates the relationship of anti-S1 IgG levels to severity of symptoms. Table 1 is a tabular summary of these data. All patients who had severity indexes ≥3 sought medical attention, admitted to hospital, admitted to ICU, on ventilator had positive antibody levels. Although 4 patients with mild symptoms had antibody levels in the normal range, both asymptomatic patients had appreciable antibody levels. These patients were close contacts of more severely affected patients. The highest antibody level recorded is severity index level 2 patient moderate symptoms, did not seek medical care. It is important to note that both asymptomatic patients had easily detectable antibody levels in saliva, suggesting this test may be useful in general population screening. Paired saliva and plasma samples We obtained 14 paired, blinded plasma and saliva samples. The plasma was analyzed by an FDA EUA-cleared ELISA test purchased from EUROIMMUN see Methods. The saliva samples, collected in Orasure™ buffer, were analyzed by the Amperial™ assay described in Methods. After unblinding, we discovered 8 recovered COVID patients and 5 healthy patients in this series. All 5 healthy patients were negative in both the saliva and plasma assays. In 7 of the 8 recovered patients, both plasma and saliva tests were positive. There was one sample with a discrepancy between saliva and plasma, with the plasma positive and the saliva in the indeterminate range. The EUROIMMUNE ELISA assay is a semi-quantitative assay and yields an absorbance ratio rather than a quantity. Fig 9 demonstrates the relationship between the saliva quantitative results and plasma absorbance ratio for the paired plasma and saliva samples. There is a clear relationship between the 2 levels, with the higher plasma absorbance ratios associated with higher saliva quantitation. Fig 9. COVID-19 antibody level in paired saliva and plasma of COVID-19 n = 8 subjects in a blinded randomized antibodies level are measured by EUROIMMUN ELISA reported in ratio proportion of OD of calibrator to OD of sample and saliva antibodies are measured by Amperial™ in pg / ml. Green dashed line indicates 5 SD reference range cutoff of Amperial™ test and red dashed line is reference range for EUROIMMUN ELISA. developed a research quality assay to quantify anti-SARS-CoV-2 IgG levels in plasma see Methods. We analyzed the 13 plasma samples using this assay. The results of this experiment are shown in Fig 10. Panel A shows a log / log plot of plasma versus saliva levels showing a clustering with high plasma levels associated with high saliva levels. Panel B shows the box plot of these values, demonstrating that plasma levels are approximately 50X those of saliva. This observation explains the necessity for an extremely sensitive assay such as the Amperial™ assay in order to detect antibodies in saliva. Of note, the publication regarding saliva SARS-CoV-2 IgG detection reports levels of 25–60 mcg / ml, 1000 times less sensitive than our assay. Fig 10. Relationship of plasma anti-SARS-CoV-2 IgG levels to saliva levels measured by Amperial™ assays.A Panel A shows a log / log plot of plasma versus saliva levels showing a clustering of the positive values with high plasma levels associated with high saliva levels on the Amperial™ platform. B Box plot of COVID-19 n = 8 and healthy n = 5 subjects demonstrating that the normalized plasma levels are approximately 50X those of saliva. Longitudinal tracking of antibody levels Three of our volunteers supplied samples at weekly intervals so we could determine the stability of their antibody levels. Results appear in Fig 11. The 5 standard deviation cutoff is again shown with the dashed green line. All 3 patients continued to have detectable levels for more than 12 weeks, with the longest interval of 15 weeks. All tests were positive in all patients and antibody levels in all 3 patients remained clearly positive during the time interval studied. Patients C1 and C3 seem to have a rise in antibody level between 11 and 12 weeks post initial symptoms followed by a return to baseline level. Patient C2 might also have had a spike in antibody levels at 10 weeks. This may be result of the amnestic B-cell population becoming established. There is insufficient data at this time to determine if this is a generalized pattern. CLIA evaluation We performed a full CLIA laboratory developed test evaluation for the Amperial™ COVID-19 IgG Antibody test. The validation assayed 72 unaffected patients and 30 recovered patients and demonstrated 100% sensitivity and specificity. The intra-assay and inter-assay variability were and respectively. DiscussionWe have developed an exquisitely specific, sensitive, non-invasive saliva based quantitative assay for anti-SARS-CoV-2 IgG antibodies. Our goal was to create a quantitative assay with sufficient positive predictive value to be useful to inform individuals regarding previous infection with COVID-19. By establishing a reference range of 5 sigma above than the mean we have a theoretical analytical specificity of We plan to repeat the analysis of all positive samples to further increase analytical specificity. Since our test is non-invasive with home-collection we can also offer repeat testing on a second sample to further increase specificity. These procedures will minimize the false positives due to purely technical issues. There is still the possibility of biological false positives, however, due to cross reactivity with other infectious or environmental agents. The S1 antigen appears to be specific for SARS-CoV-2 [2, 3, 10] and in our series of 667 samples collected prior to 2019 we observed no false positive results. We cannot predict the eventual clinical specificity of this assay. At a minimum, the specificity is 667 / 668 or assuming the next control sample tested would be a false positive, but the specificity is likely to be higher. Our current sensitivity is 100% for patients with symptoms severe enough to seek medical care. For all patients, including mildly asymptomatic patients, our clinical sensitivity is 88%. Since the Amperial™ assay only requires 6 μL of collection fluid, several assays can be performed from the same sample. This allows all positives to be repeated to confirm the positive results and further increase the specificity of the assay. We will offer testing of a second, independent sample for all patients testing positive. Since saliva collection is easily be performed at home, obtaining a second sample is not difficult. For any laboratory test, the PPV is proportional to the prevalence of positivity in the population. A recent study demonstrated a prevalence of between to 6% in Britain [17]. Using the minimum specificity of and a prevalence of 6% the Amperial™ saliva assay would have a minimum PPV of 96%. In contrast, a published saliva antibody detection assay reported a specificity of 98% with a similar sensitivity 89%. This specificity leads to PPV of only 69% making it an ineffective tool for population screening. Our data demonstrate that the Imperial™ assay is appropriate for longitudinal screening of antibody levels, a particular utility in vaccine trials and in population monitoring following mass immunization. Since this assay is quantitative and levels appear to be stable with time, patients may be monitored from home at frequent intervals. If antibodies raised in response to vaccination do not include IgG antibodies to S1 antigen, it is easy to rapidly develop Amperial™ antibody tests to any antigen. This requires adding the new antigen to the pyrrole solution and does not require significant alteration of assay conditions. A particular advantage of this assay is convenience. The Orasure™ collector is simple and easy to use and does not require professional monitoring for adequate collection. Home collection relieves the burden to an already stressed health care system. Vulnerable populations such as children and the elderly can be guided through the collection process by parents or other adults. It is possible to obtain repeat samples to confirm positives and to perform longitudinal testing since the only requirement for testing is shipping the collecting kit. The Amperial™ IgG test is plate-based and high-throughput. An entire plate is easily processed in 2 hours, leading to rapid turnaround time once the sample enters the laboratory. There is no pre-processing of the sample required; samples are taken directly from the collection vial and placed into the assay. With standard liquid handlers, the assay may be easily automated allowing for extremely high-throughput since the Amperial™ reader is only required for the polymerization step of less than a minute at the beginning of the assay and 3 minutes for the measurement phase at the end of the assay. Published data [13] and our own demonstrate a correlation between blood results and saliva results indicating that the IgG present in saliva is most likely derived from the plasma through filtration. Our data shows that saliva IgG levels are approximately 50-fold less than those in plasma necessitating a highly sensitive assay in order to detect the IgG levels in saliva. There is some discussion in the literature of the role antibody testing may have in managing the COVID-19 epidemic. Alter and Seder published an editorial in the New England Journal of Medicine arguing, “Contrary to recent reports suggesting that SARS-CoV-2 RNA testing alone, in the absence of antibodies, will be sufficient to track and contain the pandemic, the cost, complexity, and transient nature of RNA testing for pathogen detection render it an incomplete metric of viral spread at the population level. Instead, the accurate assessment of antibodies during a pandemic can provide important population-based data on pathogen exposure, facilitate an understanding of the role of antibodies in protective immunity, and guide vaccine development [14]”. ConclusionIn this article, we describe the development of a non-invasive, home collection based, exquisitely specific, and acceptably sensitive test for the presence of anti-SARS-CoV-2 antibodies in saliva. This may be an important tool in controlling the pandemic and facilitating and understanding of the role of antibody production in COVID-19 immunity. Longitudinal monitoring of anti-SARS-CoV-2 IgG levels could also play a valuable role in vaccine development and deployment by allowing longitudinal quantitative assessment of antibody levels. If the presence of detectable anti-COVID-19 IgG is shown to be an indicator of immunity to reinfection, measurement of these antibodies could allow individuals to safely return to work, school and community. The Amperial™ SARS-CoV-2 assay fulfills the requirements for all of these applications. References1. Guan W, Ni Z, Hu Y, Liang W, Ou C, He J, et al. Clinical Characteristics of Coronavirus Disease 2019 in China. New Eng J Med. 2020 Apr;382181708–20. pmid32109013 View Article PubMed/NCBI Google Scholar 2. Interim Guidelines for COVID-19 Antibody Testing. Center for Disease Control and Prevention. 2020 Aug 1. [Cited 2020 Nov 5] 3. Hoffman T, Nissen K, Krambach J, Ronnberg B, Akaberi D, Esmaeilzadeh , et al. Evaluation of a COVID-19 IgM and IgG rapid test; an efficient tool for assessment of past exposure to SARS-CoV-2. Infection Ecology and Epidemiology. 2020 Jan 1;1011754538. pmid32363011 View Article PubMed/NCBI Google Scholar 4. Montesinos I, Gruson D, Kabamba B, Dahma H, Wijngaert S, Reza S, et al. Evaluation of two automated and three rapid lateral flow immunoassays for the detection of SARS CoV-2 antibodies. Journal of Clinical Virology. 2020 Jul;128104413. pmid32403010 View Article PubMed/NCBI Google Scholar 5. Döhla M, Boesecke C, Schulte B, Diegmann C, Sib E, Richter E, et al. Rapid point-of-care testing for SARS-CoV-2 in a community screening setting shows low sensitivity. Public Health. 2020 May;182170–172. pmid32334183 View Article PubMed/NCBI Google Scholar 6. Rashid Z, Othman S, Samat M, Ali U, Wong K. Diagnostic performance of COVID-19 serology assays, Malaysian J Pathol, 2020 Apr;42113–21. View Article Google Scholar 7. Thevis M, Knoop A, Schafer M, Dufaux B, Schrader Y, Thomas A, et al. Can dried blood spots DBS contribute to conducting comprehensive SARS-CoV-2 antibody tests? Drug Test Analy. 2020 Jul;127994–7. pmid32386354 View Article PubMed/NCBI Google Scholar 8. Sun B, Feng Y, Mo X, Zheng P, Wang Q, Li P, et al. Kinetics of SARS-CoV-2 specific IgM and IgG responses in COVID-19 patients. Emerging Microbes and Infections. 2020 Jan 1;91940–948. pmid32357808 View Article PubMed/NCBI Google Scholar 9. Shi Y, Wang Y, Shao C, Huang J, Gan J, Huang X, et al. COVID-19 infection the perspectives on immune response. Cell Death and Differentiation. 2020 May;275 1451–1454. pmid32205856 View Article PubMed/NCBI Google Scholar 10. Gudbjartsson D, Norddahl G, Melsted P, Gunnarsdottir K, Holm H, Eythorsson E, et al. Humeral immune response to SARS-CoV-2 in Iceland. N Engl J Med. 2020 Oct 29;383181724–1734. pmid32871063 View Article PubMed/NCBI Google Scholar 11. Okba N, Muller M, Li W, Wang C, GeurtsvanKessel C, Corman V, et al. Severe Acute Respiratory Syndrome Coronavirus 2 –Specific Antibody Responses in Coronavirus Disease Patients. Emerg Infect Dis. 2020 Jul;26 71478–88. pmid32267220 View Article PubMed/NCBI Google Scholar 12. Hettegger P, Huber J, Pabecker K, Soldo R, Kegler U, Nöhammer C, et al. High similarity of IgG antibody profiles in blood and saliva opens opportunities for saliva based serology. PLoS ONE. 2019 Jun 20;146e0218456. pmid31220138 View Article PubMed/NCBI Google Scholar 13. Isho B, Abe KT, Zuo M, Jamal A, Rathod B, Wang J, et al. Persistence of serum and saliva antibody responses to SARS-CoV-2 spike antigens in COVID-19 patients. Sci Immunol. 2020 Oct 8;552eabe5511. pmid33033173 View Article PubMed/NCBI Google Scholar 14. Alter G, Seder R. The power of Antibody-Based Surveillance. N Engl J Med. 2020 Oct 29;383181782–1784. pmid32871061 View Article PubMed/NCBI Google Scholar 15. Wei F, Patel P, Liao W, Chaudhry K, Zhang L, Arellano-Garcia M, et al. Electrochemical Sensor for Multiplex Biomarkers Detection. Clinical Cancer Research. 2009;15 4446–4452. pmid19509137 View Article PubMed/NCBI Google Scholar 16. Ceron J, Lamy E, Martinez-Subiela S, Lopez-Jornet P, Capela-Silva F, Eckersall P, et al. Use of Saliva for Diagnosis and Monitoring of SARS-CoV-2 A General Perspective. J Clin Med. 2020 May 15;951491. pmid32429101 View Article PubMed/NCBI Google Scholar 17. Imperial College London COVID-19 Virus Home Antibody Testing. 2020 June to September. [Cited 2020 November 5] . 2021 Dec;93126813-6817. doi Epub 2021 Aug 5. Affiliations PMID 34314037 PMCID PMC8427121 DOI Free PMC article The dynamics of quantitative SARS-CoV-2 antispike IgG response to BNT162b2 vaccination Shun Kaneko et al. J Med Virol. 2021 Dec. Free PMC article Abstract Vaccination for SARS-CoV-2 is necessary to overcome coronavirus disease 2019 COVID-19. However, the time-dependent vaccine-induced immune response is not well understood. This study aimed to investigate the dynamics of SARS-CoV-2 antispike immunoglobulin G IgG response. Medical staff participants who received two sequential doses of the BNT162b2 vaccination on days 0 and 21 were recruited prospectively from the Musashino Red Cross Hospital between March and May 2021. The quantitative antispike receptor-binding domain RBD IgG antibody responses were measured using the Abbott SARS-CoV-2 IgGII Quant assay cut off ≥50 AU/ml. A total of 59 participants without past COVID-19 history were continuously tracked with serum samples. The median age was 41 22-75 years, and 14 participants were male The median antispike RBD IgG and seropositivity rates were 0 AU/ml, AU/ml, AU/ml, 18, AU/ml, and 0%, 0%, and 100% on days 0, 3, 14, and 28 after the first vaccination, respectively. The antispike RBD IgG levels were significantly increased after day 14 from vaccination p < The BNT162b2 vaccination led almost all participants to obtain serum antispike RBD IgG 14 days after the first dose. Keywords COVID-19; SARS-Cov-2; mRNA vaccine; quantitative antispike RBD IgG. © 2021 Wiley Periodicals LLC. Conflict of interest statement The authors declare that there are no conflict of interests. Figures Figure 1 Dynamics of SARS‐CoV‐2 antispike RBD IgG response after vaccination. A Schema of the schedule for vaccination and blood test. B Antispike RBD IgG titer AU/ml and seropositive rate of antispike RBD IgG and antinucleocapsid IgG in a time‐dependent manner. RBD, receptor‐binding domain Similar articles Evaluation of Humoral Immune Response after SARS-CoV-2 Vaccination Using Two Binding Antibody Assays and a Neutralizing Antibody Assay. Nam M, Seo JD, Moon HW, Kim H, Hur M, Yun YM. Nam M, et al. Microbiol Spectr. 2021 Dec 22;93e0120221. doi Epub 2021 Nov 24. Microbiol Spectr. 2021. PMID 34817223 Free PMC article. Healthcare Workers in South Korea Maintain a SARS-CoV-2 Antibody Response Six Months After Receiving a Second Dose of the BNT162b2 mRNA Vaccine. Choi JH, Kim YR, Heo ST, Oh H, Kim M, Lee HR, Yoo JR. Choi JH, et al. Front Immunol. 2022 Jan 31;13827306. doi eCollection 2022. Front Immunol. 2022. PMID 35173736 Free PMC article. Evaluation of Seropositivity Following BNT162b2 Messenger RNA Vaccination for SARS-CoV-2 in Patients Undergoing Treatment for Cancer. Massarweh A, Eliakim-Raz N, Stemmer A, Levy-Barda A, Yust-Katz S, Zer A, Benouaich-Amiel A, Ben-Zvi H, Moskovits N, Brenner B, Bishara J, Yahav D, Tadmor B, Zaks T, Stemmer SM. Massarweh A, et al. JAMA Oncol. 2021 Aug 1;781133-1140. doi JAMA Oncol. 2021. PMID 34047765 Free PMC article. Evaluation of the SARS-CoV-2 Antibody Response to the BNT162b2 Vaccine in Patients Undergoing Hemodialysis. Yau K, Abe KT, Naimark D, Oliver MJ, Perl J, Leis JA, Bolotin S, Tran V, Mullin SI, Shadowitz E, Gonzalez A, Sukovic T, Garnham-Takaoka J, de Launay KQ, Takaoka A, Straus SE, McGeer AJ, Chan CT, Colwill K, Gingras AC, Hladunewich MA. Yau K, et al. JAMA Netw Open. 2021 Sep 1;49e2123622. doi JAMA Netw Open. 2021. PMID 34473256 Free PMC article. Review of SARS-CoV-2 Antigen and Antibody Testing in Diagnosis and Community Surveillance. Nerenz RD, Hubbard JA, Cervinski MA. Nerenz RD, et al. Clin Lab Med. 2022 Dec;424687-704. doi Clin Lab Med. 2022. PMID 36368790 Free PMC article. Review. No abstract available. Cited by Higher Immunological Response after BNT162b2 Vaccination among COVID-19 Convalescents-The Data from the Study among Healthcare Workers in an Infectious Diseases Center. Skrzat-Klapaczyńska A, Kowalska JD, Paciorek M, Puła J, Bieńkowski C, Krogulec D, Stengiel J, Pawełczyk A, Perlejewski K, Osuch S, Radkowski M, Horban A. Skrzat-Klapaczyńska A, et al. Vaccines Basel. 2022 Dec 15;10122158. doi Vaccines Basel. 2022. PMID 36560567 Free PMC article. Measurements of Anti-SARS-CoV-2 Antibody Levels after Vaccination Using a SH-SAW Biosensor. Cheng CH, Peng YC, Lin SM, Yatsuda H, Liu SH, Liu SJ, Kuo CY, Wang RYL. Cheng CH, et al. Biosensors Basel. 2022 Aug 4;128599. doi Biosensors Basel. 2022. PMID 36004995 Free PMC article. Relationship between changes in symptoms and antibody titers after a single vaccination in patients with Long COVID. Tsuchida T, Hirose M, Inoue Y, Kunishima H, Otsubo T, Matsuda T. Tsuchida T, et al. J Med Virol. 2022 Jul;9473416-3420. doi Epub 2022 Mar 8. J Med Virol. 2022. PMID 35238053 Free PMC article. The Comparability of Anti-Spike SARS-CoV-2 Antibody Tests is Time-Dependent a Prospective Observational Study. Perkmann T, Mucher P, Perkmann-Nagele N, Radakovics A, Repl M, Koller T, Schmetterer KG, Bigenzahn JW, Leitner F, Jordakieva G, Wagner OF, Binder CJ, Haslacher H. Perkmann T, et al. Microbiol Spectr. 2022 Feb 23;101e0140221. doi Epub 2022 Feb 23. Microbiol Spectr. 2022. PMID 35196824 Free PMC article. References Guan WJ, Ni ZY, Hu Y, et al. Clinical characteristics of coronavirus disease 2019 in China. N Engl J Med. 2020;382181708‐1720. - PMC - PubMed Zhou F, Yu T, Du R, et al. Clinical course and risk factors for mortality of adult inpatients with COVID‐19 in Wuhan, China a retrospective cohort study. Lancet. 2020;395102291054‐1062. - PMC - PubMed Zheng Z, Peng F, Xu B, et al. Risk factors of critical & mortal COVID‐19 cases a systematic literature review and meta‐analysis. J Infect. 2020;8116. - PMC - PubMed Hu Y, Sun J, Dai Z, et al. Prevalence and severity of corona virus disease 2019 COVID‐19 a systematic review and meta‐analysis. J Clin Virol. 2020;127104371. - PMC - PubMed World Health Organization . Coronavirus disease COVID‐19. Situation report. Accessed, May 17th, MeSH terms Substances LinkOut - more resources Full Text Sources Europe PubMed Central Ovid Technologies, Inc. PubMed Central Wiley Medical Genetic Alliance MedlinePlus Health Information Miscellaneous NCI CPTAC Assay Portal . 2021 Mar 19;594e03149-20. doi Print 2021 Mar 19. Affiliations PMID 33483360 PMCID PMC8092751 DOI Free PMC article Quantitative Measurement of Anti-SARS-CoV-2 Antibodies Analytical and Clinical Evaluation Victoria Higgins et al. J Clin Microbiol. 2021. Free PMC article Abstract The severe acute respiratory syndrome coronavirus 2 SARS-CoV-2 is the causative agent of coronavirus disease 2019 COVID-19. Molecular-based testing is used to diagnose COVID-19, and serologic testing of antibodies specific to SARS-CoV-2 is used to detect past infection. While most serologic assays are qualitative, a quantitative serologic assay was recently developed that measures antibodies against the S protein, the target of vaccines. Quantitative antibody determination may help determine antibody titer and facilitate longitudinal monitoring of the antibody response, including antibody response to vaccines. We evaluated the quantitative Roche Elecsys anti-SARS-CoV-2 S assay. Specimens from 167 PCR-positive patients and 103 control specimens were analyzed using the Elecsys anti-SARS-CoV-2 S assay on the cobas e411 Roche Diagnostics. Analytical evaluation included assessing linearity, imprecision, and analytical sensitivity. Clinical evaluation included assessing clinical sensitivity, specificity, cross-reactivity, positive predictive value PPV, negative predictive value NPV, and serial sampling from the same patient. The Elecsys anti-SARS-CoV-2 S assay exhibited its highest sensitivity at 15 to 30 days post-PCR positivity and exhibited no cross-reactivity, a specificity and PPV of 100%, and an NPV between and at ≥14 days post-PCR positivity, depending on the seroprevalence estimate. Imprecision was 30, 0 to 14, and ≥14 days post-PCR positivity for the quantitative Roche Elecsys anti-SARS-CoV-2 S assay using serum or plasma samples collected from 167 patients confirmed SARS-CoV-2 positive within the previous 0 to 73 days. FIG 2 Anti-SARS-CoV-2 antibody response by days post-PCR positivity in five patients as measured by the quantitative Roche Elecsys anti-SARS-CoV-2 S assay. Similar articles Anti-SARS-CoV-2 IgM improves clinical sensitivity early in disease course. Higgins V, Fabros A, Wang XY, Bhandari M, Daghfal DJ, Kulasingam V. Higgins V, et al. Clin Biochem. 2021 Apr;901-7. doi Epub 2021 Jan 19. Clin Biochem. 2021. PMID 33476578 Free PMC article. Analytical and Clinical Evaluation of the Automated Elecsys Anti-SARS-CoV-2 Antibody Assay on the Roche cobas e602 Analyzer. Chan CW, Parker K, Tesic V, Baldwin A, Tang NY, van Wijk XMR, Yeo KJ. Chan CW, et al. Am J Clin Pathol. 2020 Oct 13;1545620-626. doi Am J Clin Pathol. 2020. PMID 32814955 Free PMC article. Head-to-Head Comparison of Two SARS-CoV-2 Serology Assays. Merrill AE, Jackson JB, Ehlers A, Voss D, Krasowski MD. Merrill AE, et al. J Appl Lab Med. 2020 Nov 1;561351-1357. doi J Appl Lab Med. 2020. PMID 32717056 Free PMC article. [SARS-CoV-2 and Microbiological Diagnostic Dynamics in COVID-19 Pandemic]. Erensoy S. Erensoy S. Mikrobiyol Bul. 2020 Jul;543497-509. doi Mikrobiyol Bul. 2020. PMID 32755524 Review. Turkish. Performance of Elecsys Anti-SARS CoV-2 Roche and VIDAS Anti-SARS CoV-2 Biomérieux for SARS-CoV-2 Nucleocapsid and Spike Protein Antibody Detection. Inés RM, Gabriela HTM, Paula CM, Magdalena TM, Jimena A, Salome KB, Javier AJ, Sebastián B, Lorena S, Adrián DL, Elisa R, Mauricio B, Tersita BM, Verónica GS, Beatriz IM. Inés RM, et al. EJIFCC. 2022 Aug 8;332159-165. eCollection 2022 Aug. EJIFCC. 2022. PMID 36313907 Free PMC article. Review. Cited by Association between reactogenicity and immunogenicity after BNT162b2 booster vaccination a secondary analysis of a prospective cohort study. Jorda A, Bergmann F, Ristl R, Radner H, Sieghart D, Aletaha D, Zeitlinger M. Jorda A, et al. Clin Microbiol Infect. 2023 May 25S1198-743X2300252-5. doi Online ahead of print. Clin Microbiol Infect. 2023. PMID 37244466 Free PMC article. Variation in antibody titers determined by Abbott and Roche Elecsys SARS-CoV-2 assays in vaccinated healthcare workers. Nakai M, Yokoyama D, Sato T, Sato R, Kojima C, Shimosawa T. Nakai M, et al. Heliyon. 2023 Jun;96e16547. doi Epub 2023 May 22. Heliyon. 2023. PMID 37235203 Free PMC article. Anti-N SARS-CoV-2 assays for evaluation of natural viral infection. Gaeta A, Angeloni A, Napoli A, Pucci B, Cinti L, Roberto P, Colaiacovo F, Berardelli E, Farina A, Antonelli G, Anastasi E. Gaeta A, et al. J Immunol Methods. 2023 Jul;518113486. doi Epub 2023 May 6. J Immunol Methods. 2023. PMID 37156408 Free PMC article. Humoral Immune Response Following SARS-CoV-2 mRNA Vaccination and Infection in Pediatric-Onset Multiple Sclerosis. Breu M, Lechner C, Schneider L, Tobudic S, Winkler S, Siegert S, Baumann M, Seidl R, Berger T, Kornek B. Breu M, et al. Pediatr Neurol. 2023 Jun;14319-25. doi Epub 2023 Mar 2. Pediatr Neurol. 2023. PMID 36966598 Free PMC article. SARS-CoV-2-reactive antibody waning, booster effect and breakthrough SARS-CoV-2 infection in hematopoietic stem cell transplant and cell therapy recipients at one year after vaccination. Piñana JL, Martino R, Vazquez L, López-Corral L, Pérez A, Chorão P, Avendaño-Pita A, Pascual MJ, Sánchez-Salinas A, Sanz-Linares G, Olave MT, Arroyo I, Tormo M, Villalon L, Conesa-Garcia V, Gago B, Terol MJ, Villalba M, Garcia-Gutierrez V, Cabero A, Hernández-Rivas JÁ, Ferrer E, García-Cadenas I, Teruel A, Navarro D, Cedillo Á, Sureda A, Solano C; Spanish Hematopoietic Stem Cell Transplantation and Cell Therapy Group GETH-TC. Piñana JL, et al. Bone Marrow Transplant. 2023 May;585567-580. doi Epub 2023 Feb 28. Bone Marrow Transplant. 2023. PMID 36854892 Free PMC article. References Carter LJ, Garner LV, Smoot JW, Li Y, Zhou Q, Saveson CJ, Sasso JM, Gregg AC, Soares DJ, Beskid TR, Jervey SR, Liu C. 2020. Assay techniques and test development for COVID-19 diagnosis. ACS Cent Sci 6591–605. doi - DOI - PMC - PubMed Van Caeseele P, Bailey D, Forgie SE, Dingle TC, Krajden M, COVID-19 Immunity Task Force. 2020. SARS-CoV-2 COVID-19 serology implications for clinical practice, laboratory medicine and public health. CMAJ 192E973–E979. doi - DOI - PMC - PubMed Deeks JJ, Dinnes J, Takwoingi Y, Davenport C, Spijker R, Taylor-Phillips S, Adriano A, Beese S, Dretzke J, Ferrante di Ruffano L, Harris IM, Price MJ, Dittrich S, Emperador D, Hooft L, Leeflang MM, Van den Bruel A, Cochrane COVID-19 Diagnostic Test Accuracy Group. 2020. Antibody tests for identification of current and past infection with SARS-CoV-2. Cochrane Database Syst Rev 6CD013652. doi - DOI - PMC - PubMed Long Q-X, Liu B-Z, Deng H-J, Wu G-C, Deng K, Chen Y-K, Liao P, Qiu J-F, Lin Y, Cai X-F, Wang D-Q, Hu Y, Ren J-H, Tang N, Xu Y-Y, Yu L-H, Mo Z, Gong F, Zhang X-L, Tian W-G, Hu L, Zhang X-X, Xiang J-L, Du H-X, Liu H-W, Lang C-H, Luo X-H, Wu S-B, Cui X-P, Zhou Z, Zhu M-M, Wang J, Xue C-J, Li X-F, Wang L, Li Z-J, Wang K, Niu C-C, Yang Q-J, Tang X-J, Zhang Y, Liu X-M, Li J-J, Zhang D-C, Zhang F, Liu P, Yuan J, Li Q, Hu J-L, Chen J, et al. 2020. Antibody responses to SARS-CoV-2 in patients with COVID-19. Nat Med 26845–848. doi - DOI - PubMed Kofler N, Baylis F. 2020. Ten reasons why immunity passports are a bad idea. Nature 581379–381. doi - DOI - PubMed MeSH terms Substances LinkOut - more resources Full Text Sources Atypon Europe PubMed Central PubMed Central Other Literature Sources scite Smart Citations Medical Genetic Alliance MedlinePlus Health Information Miscellaneous NCI CPTAC Assay Portal

anti sars cov 2 kuantitatif