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Thon V, Piler P, Pavlík T, Andrýsková L, Doležel K, Kostka D, Pikhart H, Bobák M, Klánová J. 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. BMJ Open 2023; 13:e068258. [PMID: 36898746 PMCID: PMC10008433 DOI: 10.1136/bmjopen-2022-068258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/12/2023] Open
Abstract
OBJECTIVE Examine changes in SARS-CoV-2 seropositivity before and during the national vaccination campaign in the Czech Republic. DESIGN Prospective national population-based cohort study. SETTING Masaryk University, RECETOX, Brno. PARTICIPANTS 22 130 persons provided blood samples at two time points approximately 5-7 months apart, between October 2020 and March 2021 (phase I, before vaccination), and between April and September 2021 (during vaccination campaign). OUTCOME MEASURES Antigen-specific humoral immune response was analysed by detection of IgG antibodies against the SARS-CoV-2 spike protein by commercial chemiluminescent immunoassays. Participants completed a questionnaire that included personal information, anthropometric data, self-reported results of previous RT-PCR tests (if performed), history of symptoms compatible with COVID-19 and records of COVID-19 vaccination. Seroprevalence was compared between calendar periods, previous RT-PCR results, vaccination and other individual characteristics. RESULTS Before vaccination (phase I), seroprevalence increased from 15% in October 2020 to 56% in March 2021. By the end of phase II, in September 2021, prevalence increased to 91%; the highest seroprevalence was seen among vaccinated persons with and without previous SARS-CoV-2 infection (99.7% and 97.2%, respectively), while the lowest seroprevalence was found among unvaccinated persons with no signs of disease (26%). Vaccination rates were lower in persons who were seropositive in phase I but increased with age and body mass index. Only 9% of unvaccinated subjects who were seropositive in phase I became seronegative by phase II. CONCLUSIONS The rapid increase in seropositivity during the second wave of the COVID-19 epidemic (covered by phase I of this study) was followed by a similarly steep rise in seroprevalence during the national vaccination campaign, reaching seropositivity rates of over 97% among vaccinated persons.
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Affiliation(s)
- Vojtěch Thon
- RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Pavel Piler
- RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Tomáš Pavlík
- Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Lenka Andrýsková
- RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic
| | | | - David Kostka
- Health Insurance Company of the Ministry of the Interior of the Czech Republic, Prague, Czech Republic
| | - Hynek Pikhart
- RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK
| | - Martin Bobák
- RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic
- Department of Epidemiology and Public Health, University College London, London WC1E 6BT, UK
| | - Jana Klánová
- RECETOX, Faculty of Science, Masaryk University, Brno, Czech Republic
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Piler P, Thon V, Andrýsková L, Doležel K, Kostka D, Pavlík T, Dušek L, Pikhart H, Bobák M, Matic S, Klánová J. Nationwide increases in anti-SARS-CoV-2 IgG antibodies between October 2020 and March 2021 in the unvaccinated Czech population. Commun Med (Lond) 2022; 2:19. [PMID: 35603283 PMCID: PMC9053194 DOI: 10.1038/s43856-022-00080-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/24/2022] [Indexed: 01/13/2023] Open
Abstract
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.
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Affiliation(s)
- Pavel Piler
- grid.10267.320000 0001 2194 0956RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Vojtěch Thon
- grid.10267.320000 0001 2194 0956RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Lenka Andrýsková
- grid.10267.320000 0001 2194 0956RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Kamil Doležel
- QualityLab Association, Evropská 846/176a, Prague, Czech Republic
| | - David Kostka
- grid.436106.6Health Insurance Company of the Ministry of the Interior of the Czech Republic, Vinohradská 2577/178, 130 00 Prague, Czech Republic
| | - Tomáš Pavlík
- grid.10267.320000 0001 2194 0956Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic ,grid.486651.80000 0001 2231 0366Institute of Health Information and Statistics of the Czech Republic, Palackého náměstí 4, 128 01 Prague, Czech Republic
| | - Ladislav Dušek
- grid.10267.320000 0001 2194 0956Institute of Biostatistics and Analyses, Faculty of Medicine, Masaryk University, Kamenice 3, 625 00 Brno, Czech Republic ,grid.486651.80000 0001 2231 0366Institute of Health Information and Statistics of the Czech Republic, Palackého náměstí 4, 128 01 Prague, Czech Republic
| | - Hynek Pikhart
- grid.10267.320000 0001 2194 0956RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic ,grid.83440.3b0000000121901201Department of Epidemiology & Public Health, University College London, 1 – 19 Torrington Place, London, WC1E 6BT UK
| | - Martin Bobák
- grid.10267.320000 0001 2194 0956RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic ,grid.83440.3b0000000121901201Department of Epidemiology & Public Health, University College London, 1 – 19 Torrington Place, London, WC1E 6BT UK
| | - Srdan Matic
- World Health Organization (WHO), Country Office in the Czech Republic, Rytířská 31, 110 00 Prague, Czech Republic
| | - Jana Klánová
- grid.10267.320000 0001 2194 0956RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
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Piler P, Thon V, Andrýsková L, Doležel K, Kostka D, Pavlík T, Dušek L, Pikhart H, Bobák M, Matic S, Klánová J. Nationwide increases in anti-SARS-CoV-2 IgG antibodies between October 2020 and March 2021 in the unvaccinated Czech population. Commun Med (Lond) 2022. [PMID: 35603283 DOI: 10.1038/s43856-022-00080-0.pmid:35603283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023] Open
Abstract
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.
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Affiliation(s)
- Pavel Piler
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Vojtěch Thon
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Lenka Andrýsková
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
| | - Kamil Doležel
- QualityLab Association, Evropská 846/176a, Prague, Czech Republic
| | - David Kostka
- Health Insurance Company of the Ministry of the Interior of the Czech Republic, Vinohradská 2577/178, 130 00 Prague, Czech Republic
| | - Tomáš Pavlík
- 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
| | - Ladislav Dušek
- 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
| | - Hynek Pikhart
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
- Department of Epidemiology & Public Health, University College London, 1 - 19 Torrington Place, London, WC1E 6BT UK
| | - Martin Bobák
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
- Department of Epidemiology & Public Health, University College London, 1 - 19 Torrington Place, London, WC1E 6BT UK
| | - Srdan Matic
- World Health Organization (WHO), Country Office in the Czech Republic, Rytířská 31, 110 00 Prague, Czech Republic
| | - Jana Klánová
- RECETOX, Faculty of Science, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
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