Assessment of Seroprevalence, Immune Response Patterns, and COVID-19 Incidence Following CoronaVac Vaccination in a Fully Vaccinated Small Municipality in Northeast Brazil: A Population-Based Surveillance Analysis

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Brazil experienced over 38 million COVID-19 cases and 708 thousand deaths by the end of 2023, highlighting the pandemic's severity.
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Guaramiranga, Ceará, achieved 100% vaccination coverage for its adult population against COVID-19, making it a unique study site.
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The study assessed seroprevalence of neutralizing IgG antibodies and the immune response duration in vaccinated residents of Guaramiranga.
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CoronaVac, the first vaccine used widely in Brazil, demonstrated effectiveness in preventing severe COVID-19, though data in small communities is limited.
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The research included a cross-sectional seroepidemiological survey and a retrospective cohort analysis to evaluate vaccine impact on COVID-19 incidence.

Bmc Infectious Diseases

by Lourrany Borges Costa, Francisca Kalline de Almeida Barreto, Patrícia Pereira Lima Barbosa, Magda Moura de Almeida, Antonia Luciana Souza Bekman, Silvana Soares de Souza, Ana Carolina Barjud Marques Máximo, Debora Bezerra Silva, Carlos Henrique Alencar, Luciano Pamplona de Góes Cavalcanti
March 13, 2026

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