Background
Peru has the highest mortality from COVID-19 globally, and the start of vaccination in February-2021 have given a lot of hope in the midst of the rise of the 2nd wave of the pandemic, with health personnel being the first to receive the vaccine.
Objective: Determine the effectiveness of the BBIBP-Corv vaccine in health personnel in the less socially favored Region, the Andean Trapeze-Peru.
Methods
Retrospective cohort study in health personnel (11,505 unvaccinated/44,201 vaccinated with 2 doses) older than 18 years old between February-June 2021 in Apurimac, Ayacucho, Cusco, Huancavelica and Puno Regions. Secondary information from the MOH was used, including: vaccination records, laboratory results, hospital information and death registration. Interdose period was 21 days, with follow-up for 14 weeks, until detection of the events of infection, hospitalization or death. For the vaccinated cohort, the subject was considered infected if it had a positive PCR/Antigenic test result 14 days after the 2nd dose. Vaccine effectiveness (VE) and 95%CI were calculated using STATA v.16. Additionally, VE was estimated in people 60 years old or older (VE60+).
Results
2,067 SARS-CoV2 cases were confirmed by PCR/antigen test (1,367 received 2 doses and 700 were unvaccinated). To prevent infection, the VE=28.4%,95%CI[21.5-34.7];VE60+=27.7%[20.8-34.1]. There were 86 hospitalized for COVID-19 (27 vaccinated and 59 unvaccinated). To prevent hospitalization, VE=82.5%[71.9- 89.3];VE60+=84.8%[75.8-90.4]. 19 deaths from COVID-19 were reported (1 vaccinated and 18 unvaccinated). To prevent deaths, VE=97.9%[86.9-99.9];VE60+=98.6%[89.2-99.8] were found. The national effectiveness was VE=36.8%[34.7-38.7], VE=80.2%[76.1-83.6] and VE=94.6%[92.0-96.5] for the three events studied, respectively. The lowest vaccine efficacies to prevent infection VE=24.5%;VE60+=26.5%, and to prevent deaths VE=88.6%;VE60+=90.3% were in Puno; and to prevent hospitalization VE=82.5%;VE60+=77.6% in Cusco. Values were adjusted by Poisson regression.
Conclusion
The effectiveness of BBIBP-Corv vaccine to prevent infection (VE=28.4%,95%CI[21.5-34.7]) in the Andean Trapeze is significantly lower than the national average. No remarcable differences were found for hospitalization and death.