Effectiveness of an inactivated Covid-19 vaccine with homologous and heterologous boosters against Omicron in Brazil

• Type of Material: Article
• Authors: Otavio T Ranzani, Universitat Pompeu Fabra (UPF); Matt DT Hitchings, University of Florida; Rosana Leite de Melo, Ministério da Saúde; Giovanny VA de Franca, Ministério da Saúde; Cássia de Fátima R Fernandes, Ministério da Saúde; Margaret L Lind, Yale School of Public Health; Mario Sergio Scaramuzzini Torres, Municipal Health Secretary of Manaus; Daniel Henrique Tsuha, Fundação Oswaldo Cruz; Leticia CS David, Pan American Health Organization; Rodrigo FC Said, Pan American Health Organization; Maria Almiron, Pan American Health Organization; Roberto D de Oliveira, Univ Estadual Mato Grosso do Sul; Natalie Dean, Emory University; Derek AT Cummings, University of Florida; Jason R Andrews, Stanford University; Albert I Ko, Yale School of Public Health; Julio Croda, Yale School of Public Health
• Language: English
• Date: 2022-10-06
• Publisher: NATURE PORTFOLIO
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2022
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41467-022-33169-0
• Title of Journal or Parent Work: NATURE COMMUNICATIONS
• Volume: 13
• Issue: 1
• Start Page: 5536
• End Page: 5536
• Keywords: Multidisciplinary Sciences; Science & Technology; Science & Technology - Other Topics
• Research Categories: Health Sciences, Epidemiology

Abstract

The effectiveness of inactivated vaccines (VE) against symptomatic and severe COVID-19 caused by omicron is unknown. We conducted a nationwide, test-negative, case-control study to estimate VE for homologous and heterologous (BNT162b2) booster doses in adults who received two doses of CoronaVac in Brazil in the Omicron context. Analyzing 1,386,544 matched-pairs, VE against symptomatic disease was 8.6% (95% CI, 5.6–11.5) and 56.8% (95% CI, 56.3–57.3) in the period 8–59 days after receiving a homologous and heterologous booster, respectively. During the same interval, VE against severe Covid-19 was 73.6% (95% CI, 63.9–80.7) and 86.0% (95% CI, 84.5–87.4) after receiving a homologous and heterologous booster, respectively. Waning against severe Covid-19 after 120 days was only observed after a homologous booster. Heterologous booster might be preferable to individuals with completed primary series inactivated vaccine.