Effectiveness of an Inactivated SARS-CoV-2 Vaccine in Chile.
N Engl J Med
; 385(10): 875-884, 2021 09 02.
Article
in En
| MEDLINE
| ID: mdl-34233097
ABSTRACT
BACKGROUND:
Mass vaccination campaigns to prevent coronavirus disease 2019 (Covid-19) are occurring in many countries; estimates of vaccine effectiveness are urgently needed to support decision making. A countrywide mass vaccination campaign with the use of an inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine (CoronaVac) was conducted in Chile starting on February 2, 2021.METHODS:
We used a prospective national cohort, including participants 16 years of age or older who were affiliated with the public national health care system, to assess the effectiveness of the inactivated SARS-CoV-2 vaccine with regard to preventing Covid-19 and related hospitalization, admission to the intensive care unit (ICU), and death. We estimated hazard ratios using the extension of the Cox proportional-hazards model, accounting for time-varying vaccination status. We estimated the change in the hazard ratio associated with partial immunization (≥14 days after receipt of the first dose and before receipt of the second dose) and full immunization (≥14 days after receipt of the second dose). Vaccine effectiveness was estimated with adjustment for individual demographic and clinical characteristics.RESULTS:
The study was conducted from February 2 through May 1, 2021, and the cohort included approximately 10.2 million persons. Among persons who were fully immunized, the adjusted vaccine effectiveness was 65.9% (95% confidence interval [CI], 65.2 to 66.6) for the prevention of Covid-19 and 87.5% (95% CI, 86.7 to 88.2) for the prevention of hospitalization, 90.3% (95% CI, 89.1 to 91.4) for the prevention of ICU admission, and 86.3% (95% CI, 84.5 to 87.9) for the prevention of Covid-19-related death.CONCLUSIONS:
Our results suggest that the inactivated SARS-CoV-2 vaccine effectively prevented Covid-19, including severe disease and death, a finding that is consistent with results of phase 2 trials of the vaccine. (Funded by Agencia Nacional de Investigación y Desarrollo and others.).
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Mass Vaccination
/
Immunogenicity, Vaccine
/
COVID-19 Vaccines
/
COVID-19
Type of study:
Incidence_studies
/
Observational_studies
/
Prognostic_studies
/
Risk_factors_studies
Aspects:
Patient_preference
Limits:
Adolescent
/
Adult
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Aged
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Aged80
/
Female
/
Humans
/
Male
/
Middle aged
Country/Region as subject:
America do sul
/
Chile
Language:
En
Journal:
N Engl J Med
Year:
2021
Document type:
Article