Effectiveness of Heterologous Coronavirus Disease 2019 (COVID-19) Vaccine Booster Dosing in Brazilian Healthcare Workers, 2021. (1st July 2022)

• Record Type: Journal Article
• Authors: Marra, Alexandre R; Miraglia, João Luiz; Malheiros, Daniel Tavares; Guozhang, Yang; Teich, Vanessa Damazio; da Silva Victor, Elivane; Rebello Pinho, João Renato; Cypriano, Adriana; Vieira, Laura Wanderly; Polonio, Miria; Ornelas, Rafael Herrera; de Oliveira, Solange Miranda; Borges Junior, Flavio Araujo; Oler, Silvia Cristina Cassiano; Schettino, Guilherme de Paula Pinto; de Oliveira, Ketti Gleyzer; Ferraz Santana, Rúbia Anita; de Mello Malta, Fernanda; Amgarten, Deyvid; Boechat, Ana Laura; Trecenti, Noelly Maria Zimpel; Kobayashi, Takaaki; Salinas, Jorge L; Edmond, Michael B; Rizzo, Luiz Vicente
• Is Part Of: Clinical infectious diseases. Volume 76:Number 3(2023)
• Page Start: e360
• Page End: e366
• Publication Date: 2022-07-01
• Subjects: COVID-19 vaccine -- effectiveness -- CoronaVac -- Oxford-AstraZeneca -- Pfizer/BioNTech booster; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciac430
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract: Background: Little is currently known about vaccine effectiveness (VE) for either 2 doses of Oxford-AstraZeneca (ChAdOx1) viral vector vaccine or CoronaVac (Instituto Butantan) inactivated viral vaccine followed by a third dose of mRNA vaccine (Pfizer/BioNTech) among healthcare workers (HCWs). Methods: We conducted a retrospective cohort study among HCWs (aged ≥18 years) working in a private healthcare system in Brazil from January to December 2021. VE was defined as 1 – incidence rate ratio (IRR), with IRR determined using Poisson models with the occurrence of laboratory-confirmed coronavirus disease 2019 (COVID-19) infection as the outcome, adjusting for age, sex, and job type. We compared those receiving viral vector or inactivated viral primary series (2 doses) with those who received an mRNA booster. Results: A total of 11 427 HCWs met the inclusion criteria. COVID-19 was confirmed in 31.5% of HCWs receiving 2 doses of CoronaVac vaccine versus 0.9% of HCWs receiving 2 doses of CoronaVac vaccine with mRNA booster ( P < .001) and 9.8% of HCWs receiving 2 doses of ChAdOx1 vaccine versus 1% among HCWs receiving 2 doses of ChAdOx1 vaccine with mRNA booster ( P < .001). In the adjusted analyses, the estimated VE was 92.0% for 2 CoronaVac vaccines plus mRNA booster and 60.2% for 2 ChAdOx1 vaccines plus mRNA booster, when compared with those with no mRNA booster. Of 246 samples screened for mutations, 191 (77.6%) were Delta variants. Conclusions: While 2 doses of ChAdOx1 or CoronaVac vaccines prevent COVID-19, the addition of a Pfizer/BioNTech booster provided significantly more protection. Abstract : The viral vector and inactivated virus COVID-19 vaccines can significantly prevent COVID-19 infection among healthcare workers when boosted with a third dose of Pfizer/BioNTech vaccine. The heterologous booster strategy was effective even after emergence of SARS-CoV-2 variants (Gamma and Delta).