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Longer-term effectiveness of a heterologous coronavirus disease 2019 (COVID-19) vaccine booster in healthcare workers in Brazil
Journal article   Open access   Peer reviewed

Longer-term effectiveness of a heterologous coronavirus disease 2019 (COVID-19) vaccine booster in healthcare workers in Brazil

Alexandre Marra, João Miraglia, Daniel Tavares Malheiro, Guozhang Yang, Vanessa Damazio Teich, Elivane da Silva Victor, João Renato Rebello Pinho, Adriana Cypriano, Laura Vieira, Miria Polonio, …
Antimicrobial stewardship & healthcare epidemiology : ASHE, Vol.3(1), E104
06/01/2023
DOI: 10.1017/ash.2023.173
PMCID: PMC10311693
PMID: 37396193
Appears in  UI Libraries Support Open Access
url
https://doi.org/10.1017/ash.2023.173View
Published (Version of record) Open Access

Abstract

Objective: To compare the long-term vaccine effectiveness between those receiving viral vector [Oxford-AstraZeneca (ChAdOx1)] or inactivated viral (CoronaVac) primary series (2 doses) and those who received an mRNA booster (Pfizer/BioNTech) (the third dose) among healthcare workers (HCWs). Methods: We conducted a retrospective cohort study among HCWs (aged ≥18 years) in Brazil from January 2021 to July 2022. To assess the variation in the effectiveness of booster dose over time, we estimated the effectiveness rate by taking the log risk ratio as a function of time. Results: Of 14,532 HCWs, coronavirus disease 2019 (COVID-19) was confirmed in 56.3% of HCWs receiving 2 doses of CoronaVac vaccine versus 23.2% of HCWs receiving 2 doses of CoronaVac vaccine with mRNA booster (P < .001), and 37.1% of HCWs receiving 2 doses of ChAdOx1 vaccine versus 22.7% among HCWs receiving 2 doses of ChAdOx1 vaccine with mRNA booster (P < .001). The highest vaccine effectiveness with mRNA booster was observed 30 days after vaccination: 91% for the CoronaVac vaccine group and 97% for the ChAdOx1 vaccine group. Vacine effectiveness declined to 55% and 67%, respectively, at 180 days. Of 430 samples screened for mutations, 49.5% were SARS-CoV-2 delta variants and 34.2% were SARS-CoV-2 omicron variants. Conclusions: Heterologous COVID-19 vaccines were effective for up to 180 days in preventing COVID-19 in the SARS-CoV-2 delta and omicron variant eras, which suggests the need for a second booster.
 Immunization COVID-19 vaccines Effectiveness Einstein, Albert (1879-1955) Hospitalization Laboratories Medical personnel mRNA vaccines Pandemics Severe acute respiratory syndrome coronavirus 2 Survival analysis Ventilators UIOWA OA Agreement

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