Effectiveness of the BBIPB-CorV Vaccine in Preventing Infection and Death in Health Care Workers in Peru 2021

Background: In February 2021, Peru initiated its vaccination campaign for COVID-19 prevention using the inactivated virus vaccine BBIBP-CorV, prioritizing healthcare workers. Our study aims to evaluate the effectiveness of this vaccine to prevent SARS-CoV-2 infections, all-cause death and death due to COVID-19 in this population, during a period of high transmission in which the lambda variant predominated. Methods: We conducted a retrospective cohort study, from February 9 to June 30, 2021. We integrated several databases, including the national registry of Health care workers (HW) , the national registry of deaths and the national registries of SARS-CoV-2 diagnostic tests to calculate the effectiveness of the vaccine in preventing the three outcomes among partially immunized and fully immunized HW. The extension of the Cox proportional hazards regression was used to model the mortality results, and the Poisson regression was used to model SARS-CoV-2 infection, allowing in each case time-varying immunization status of the subjects. Findings:  606,772 HW were eligible for the study, 396,440 (66%) were female and the mean age was 44 (IQR: 33·0, 51·0). In fully immunized HCW, the effectiveness of the vaccine was 83·6 (95% CI: 80·2 to 86·4) for prevention of all-cause mortality, 88·7 (95% CI: 85·1 to 91·4) for COVID-19 mortality, and 40·3 (95% CI 38·9 to 41·6) for prevention of SARS-CoV-2 infection. Interpretation: The inactivated virus BBIBP-CorV vaccine was highly effective for prevention of all-cause death and COVID-19 related deaths in HCW with complete immunization. These results were consistent within different subgroups and sensitivity analyses. Funding: Peruvian National Institute of Health. Declaration of Interest: None to declare. Ethical Approval: This study was approved by the Research Ethics Committee of the Peruvian National Institute of Health (INS Peru), (ID: 10812-2021).