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

Investor logo
Investor logo
Investor logo
Investor logo

Warning

This publication doesn't include Faculty of Education. It includes Faculty of Science. Official publication website can be found on muni.cz.
Authors

THON Vojtěch PILER Pavel PAVLÍK Tomáš ANDRÝSKOVÁ Lenka DOLEŽEL Kamil KOSTKA David PIKHART Hynek BOBÁK Martin KLÁNOVÁ Jana

Year of publication 2023
Type Article in Periodical
Magazine / Source BMJ Open
MU Faculty or unit

Faculty of Science

Citation
Web https://bmjopen.bmj.com/content/13/3/e068258.long
Doi http://dx.doi.org/10.1136/bmjopen-2022-068258
Keywords SARS-CoV-2; cohort study; COVID-19
Attached files
Description 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 RTPCR 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.
Related projects:

You are running an old browser version. We recommend updating your browser to its latest version.