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EFFECTIVENESS OF CHADOX1 VACCINE IN OLDER ADULTS DURING SARS-COV-2 GAMMA VARIANT CIRCULATION IN SÃO PAULO
Hitchings, Matt D. T. et al. | Date Issued: 2021
Author
Hitchings, Matt D. T.
Ranzani, Otavio T.
Dorion, Murilo
D’Agostini, Tatiana Lang
Paula, Regiane Cardoso de
Paula, Olivia Ferreira Pereira de
Villela, Edlaine Faria de Moura
Torres, Mario Sergio Scaramuzzini
Oliveira, Silvano Barbosa de
Schulz, Wade
Almiron, Maria
Said, Rodrigo
Oliveira, Roberto Dias de
Silva, Patricia Vieira
Araújo, Wildo Navegantes de
Gorinchteyn, Jean Carlo
Andrews, Jason R.
Cummings, Derek A. T.
Ko, Albert I.
Croda, Julio
Affilliation
University of Florida. Department of Biostatistics. College of Public Health & Health Professions. Gainesville, FL, USA.
Barcelona Institute for Global Health. ISGlobal. Barcelona, Spain / Universidade de São Paulo. Faculdade de Medicina. Hospital das Clínicas HCFMUSP. Pulmonary Division, Heart Institute (InCor). São Paulo, SP, Brazil.
Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven, CT, USA.
Disease Control Coordination of the São Paulo State Department of Health. São Paulo, SP, Brazil.
Disease Control Coordination of the São Paulo State Department of Health. São Paulo, SP, Brazil.
Disease Control Coordination of the São Paulo State Department of Health. São Paulo, SP, Brazil.
Disease Control Coordination of the São Paulo State Department of Health. São Paulo, SP, Brazil.
Municipal Health Secretary of Manaus. Manaus, AM, Brazil.
Pan American Health Organization. Brasília, DF, Brazil / Universidade de Brasília. Brasília, DF, Brazil.
Yale University School of Medicine. Department of Laboratory Medicine. New Haven, CT, USA.
Pan American Health Organization. Brasília, DF, Brazil.
Pan American Health Organization. Brasília, DF, Brazil.
State University of Mato Grosso do Sul. Dourados, MS, Brazil.
Universidade Federal de Mato Grosso do Sul. Campo Grande, MS, Brazil.
Pan American Health Organization. Brasília, DF, Brazil / Universidade de Brasília, Brasília, Distrito Federal, Brazil / National Institute for Science and Technology for Health Technology Assessment. Porto Alegre, RS, Brazil.
Health Secretariat of the State of São Paulo. São Paulo, SP, Brazil.
Stanford University. Division of Infectious Diseases and Geographic Medicine. Stanford, CA, USA.
University of Florida. Department of Biology. Gainesville, FL, USA / University of Florida. Emerging Pathogens Institute. Gainesville, FL, USA.
Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven, CT, USA / Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, Bahia, Brazil.
Yale School of Public Health. Department of Epidemiology of Microbial Diseases. New Haven, CT, USA / Universidade Federal de Mato Grosso do Sul. Campo Grande, Mato Grosso do Sul, Brazil / Fundação Oswaldo Cruz. Fiocruz Mato Grosso do Sul. Campo Grande, Mato Grosso do Sul, Brazil.
Abstract
A two-dose regimen of the Oxford-AstraZeneca (ChAdOx1) Covid-19 vaccine with an inter-dose interval of three months has been implemented in many countries with restricted vaccine supply. However, there is limited evidence for the effectiveness of ChAdOx1 by dose in elderly populations in countries with high prevalence of the Gamma variant of SARS-CoV-2. Here, we estimate ChAdOx1 effectiveness by dose against the primary endpoint of RT-PCR-confirmed Covid-19, and secondary endpoints of Covid-19 hospitalization and Covid-19-related death, in adults aged ≥60 years during an epidemic with high Gamma variant prevalence in São Paulo state, Brazil using a matched, test-negative case-control study. Starting 28 days after the first dose, effectiveness of a single dose of ChAdOx1 is 33.4% (95% CI, 26.4–39.7) against Covid-19, 55.1% (95% CI, 46.6–62.2) against hospitalization, and 61.8% (95% CI, 48.9–71.4) against death. Starting 14 days after the second dose, effectiveness of the two-dose schedule is 77.9% (95% CI, 69.2–84.2) against Covid-19, 87.6% (95% CI, 78.2–92.9) against hospitalization, and 93.6% (95% CI, 81.9–97.7) against death. Completion of the ChAdOx1 vaccine schedule affords significantly increased protection over a single dose against mild and severe Covid-19 outcomes in elderly individuals during widespread Gamma variant circulation.
Keywords in Portuguese
COVID-19
Vacinas
Oxford-AstraZeneca
 
Keywords
COVID-19
Vaccines
Oxford-AstraZeneca
 
Publisher
Nature Research
Citation
HITCHINGS, Matt D. T. et.al. Effectiveness of ChAdOx1 vaccine in older adults during SARS-CoV-2 gamma variant circulation in São Paulo. Nature Communications, v. 12, n. 6220, p. 1-8, 2021.
DOI
10.1038/s41467-021-26459-6
ISSN
2041-1723