BACKGROUND: The aim of the nationwide prospective seroconversion (PROSECO) study was to investigate the dynamics of anti-SARS-CoV-2 IgG antibodies in the Czech population. Here we report on baseline prevalence from that study. METHODS: The study included the first 30,054 persons who provided a blood sample between October 2020 and March 2021. Seroprevalence was compared between calendar periods, previous RT-PCR results and other factors. RESULTS: The data show a large increase in seropositivity over time, from 28% in October/November 2020 to 43% in December 2020/January 2021 to 51% in February/March 2021. These trends were consistent with government data on cumulative viral antigenic prevalence in the population captured by PCR testing - although the seroprevalence rates established in this study were considerably higher. There were only minor differences in seropositivity between sexes, age groups and BMI categories, and results were similar between test providing laboratories. Seropositivity was substantially higher among persons with history of symptoms (76% vs. 34%). At least one third of all seropositive participants had no history of symptoms, and 28% of participants with antibodies against SARS-CoV-2 never underwent PCR testing. CONCLUSIONS: Our data confirm the rapidly increasing prevalence in the Czech population during the rising pandemic wave prior to the beginning of vaccination. The difference between our results on seroprevalence and PCR testing suggests that antibody response provides a better marker of past infection than the routine testing program.

Department of Epidemiology and Public Health University College London 1 19 Torrington Place London WC1E 6BT UK

Health Insurance Company of the Ministry of the Interior of the Czech Republic Vinohradská 2577 178 130 00 Prague Czech Republic

Institute of Biostatistics and Analyses Faculty of Medicine Masaryk University Kamenice 3 625 00 Brno Czech Republic

Institute of Health Information and Statistics of the Czech Republic Palackého náměstí 4 128 01 Prague Czech Republic

QualityLab Association Evropská 846 176a Prague Czech Republic

RECETOX Faculty of Science Masaryk University Kotlarska 2 611 37 Brno Czech Republic

World Health Organization Country Office in the Czech Republic Rytířská 31 110 00 Prague Czech Republic

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Li Q, et al. Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia. N. Engl. J. Med. 2020;382:1199–1207. doi: 10.1056/NEJMoa2001316. PubMed DOI PMC

Long Q-X, et al. Antibody responses to SARS-CoV-2 in patients with COVID-19. Nat. Med. 2020;26:845–848. doi: 10.1038/s41591-020-0897-1. PubMed DOI

Caturegli G, Materi J, Howard BM, Caturegli P. Clinical validity of serum antibodies to SARS-CoV-2: a case-control study. Ann. Intern. Med. 2020;173:614–622. doi: 10.7326/M20-2889. PubMed DOI PMC

Sakurai A, et al. Natural history of asymptomatic SARS-CoV-2 infection. N. Engl. J. Med. 2020;383:885–886. doi: 10.1056/NEJMc2013020. PubMed DOI PMC

Payne DC, et al. SARS-CoV-2 Infections and Serologic Responses from a Sample of U.S. Navy Service Members - USS Theodore Roosevelt, April 2020. Morb. Mortal. Wkly. Rep. 2020;69:714–721. doi: 10.15585/mmwr.mm6923e4. PubMed DOI PMC

Imai K, et al. Antibody response patterns in COVID-19 patients with different levels of disease severity in Japan. J Med Virol. 2021;93:3211–3218. doi: 10.1002/jmv.26899. PubMed DOI PMC

Perkmann, T. et al. Anti-spike protein assays to determine SARS-CoV-2 antibody levels: a head-to-head comparison of five quantitative assays. Microbiol Spectr.9, e0024721 (2021). PubMed PMC

Arora RK, et al. SeroTracker: a global SARS-CoV-2 seroprevalence dashboard. Lancet Infect. Dis. 2021;21:e75–e76. doi: 10.1016/S1473-3099(20)30631-9. PubMed DOI PMC

Pollán M, et al. Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study. Lancet. 2020;396:535–544. doi: 10.1016/S0140-6736(20)31483-5. PubMed DOI PMC

Carrat F, et al. Evidence of early circulation of SARS-CoV-2 in France: findings from the population-based “CONSTANCES” cohort. Eur. J. Epidemiol. 2021;36:219–222. doi: 10.1007/s10654-020-00716-2. PubMed DOI PMC

Vos ERA, et al. Nationwide seroprevalence of SARS-CoV-2 and identification of risk factors in the general population of the Netherlands during the first epidemic wave. J. Epidemiol. Community Health. 2020;75:489–495. doi: 10.1136/jech-2020-215678. PubMed DOI PMC

Apolone, G. et al. Unexpected detection of SARS-CoV-2 antibodies in the prepandemic period in Italy. Tumori, 300891620974755, 10.1177/0300891620974755 (2020).

Ward H, et al. SARS-CoV-2 antibody prevalence in England following the first peak of the pandemic. Nat. Commun. 2021;12:905. doi: 10.1038/s41467-021-21237-w. PubMed DOI PMC

Stringhini S, et al. Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Geneva, Switzerland (SEROCoV-POP): a population-based study. Lancet. 2020;396:313–319. doi: 10.1016/S0140-6736(20)31304-0. PubMed DOI PMC

Stefanelli P, et al. Prevalence of SARS-CoV-2 IgG antibodies in an area of northeastern Italy with a high incidence of COVID-19 cases: a population-based study. Clin. Microbiol. Infect. 2021;27:633.e631–633.e637. doi: 10.1016/j.cmi.2020.11.013. PubMed DOI PMC

Streeck H, et al. Infection fatality rate of SARS-CoV2 in a super-spreading event in Germany. Nat. Commun. 2020;11:5829. doi: 10.1038/s41467-020-19509-y. PubMed DOI PMC

Pritsch, M. et al. Prevalence and Risk Factors of Infection in the Representative COVID-19 Cohort Munich. Int J. Environ. Res. Public Health 18, 10.3390/ijerph18073572 (2021). PubMed PMC

Slot E, et al. Low SARS-CoV-2 seroprevalence in blood donors in the early COVID-19 epidemic in the Netherlands. Nat. Commun. 2020;11:5744. doi: 10.1038/s41467-020-19481-7. PubMed DOI PMC

Carrat, F. et al. Antibody status and cumulative incidence of SARS-CoV-2 infection among adults in three regions of France following the first lockdown and associated risk factors: a multicohort study. Int J Epidemiol. 50, 1458–1472 (2021). PubMed PMC

Rostami A, et al. SARS-CoV-2 seroprevalence worldwide: a systematic review and meta-analysis. Clin. Microbiol. Infect. 2021;27:331–340. doi: 10.1016/j.cmi.2020.10.020. PubMed DOI PMC

Anda, E. E. et al. Seroprevalence of antibodies against SARS-CoV-2 virus in the adult Norwegian population, winter 2020/2021: pre-vaccination period. Preprint at medRxiv10.1101/2021.03.23.21253730 (2021).

Soeorg, H. et al. Anti-spike protein receptor-binding domain IgG levels after COVID-19 infection or vaccination against SARS-CoV-2 in a seroprevalence study. Preprint at medRxiv10.1101/2021.06.06.21258406 (2021).

Harries, M. et al. SARS-CoV-2 seroprevalence in Germany - a population based sequential study in five regions. Preprint at medRxiv10.1101/2021.05.04.21256597 (2021).

Worldometers.info. Reported Cases and Deaths of COVID-19 by Country or Territory. https://www.worldometers.info/coronavirus/ (2021).

Czech Statistical Office. Age Distribution of the Population - 2020: Population of males and females by age as of 31 December 2020. Table code 130064-21. Available from www.czso.cz.

Hallal PC, et al. SARS-CoV-2 antibody prevalence in Brazil: results from two successive nationwide serological household surveys. Lancet Glob. Health. 2020;8:e1390–e1398. doi: 10.1016/S2214-109X(20)30387-9. PubMed DOI PMC

Reicher, S. et al. Nationwide seroprevalence of antibodies against SARS-CoV-2 in Israel. Eur. J. Epidemiol. 1-8, (2021). PubMed PMC

Russell MW, Moldoveanu Z, Ogra PL, Mestecky J. Mucosal immunity in COVID-19: a neglected but critical aspect of SARS-CoV-2 infection. Front. Immunol. 2020;11:611337. doi: 10.3389/fimmu.2020.611337. PubMed DOI PMC

World Health, O. Population-based age-stratified seroepidemiological investigation protocol for COVID-19 virus infection, 17 March 2020. (World Health Organization, Geneva, 2020).

He Y, et al. Cross-neutralization of human and palm civet severe acute respiratory syndrome coronaviruses by antibodies targeting the receptor-binding domain of spike protein. J. Immunol. 2006;176:6085–6092. doi: 10.4049/jimmunol.176.10.6085. PubMed DOI

Berry JD, et al. Neutralizing epitopes of the SARS-CoV S-protein cluster independent of repertoire, antigen structure or mAb technology. MAbs. 2010;2:53–66. doi: 10.4161/mabs.2.1.10788. PubMed DOI PMC

Jiang S, Hillyer C, Du L. Neutralizing antibodies against SARS-CoV-2 and other human coronaviruses. Trends Immunol. 2020;41:355–359. doi: 10.1016/j.it.2020.03.007. PubMed DOI PMC

Anand S, et al. Prevalence of SARS-CoV-2 antibodies in a large nationwide sample of patients on dialysis in the USA: a cross-sectional study. Lancet. 2020;396:1335–1344. doi: 10.1016/S0140-6736(20)32009-2. PubMed DOI PMC

Long-Term Immunological Alertness and Response to COVID-19 Vaccination-Conditions for Prevention in Early Palliative Oncological Care Patients

Investigation of SARS-CoV-2 seroprevalence in relation to natural infection and vaccination between October 2020 and September 2021 in the Czech Republic: a prospective national cohort study

Comparison of Two Commercially Available Interferon-γ Release Assays for T-Cell-Mediated Immunity and Evaluation of Humoral Immunity against SARS-CoV-2 in Healthcare Workers