Effectiveness of whole virus COVID-19 vaccine at protecting health care personnel against SARS-CoV-2 infections in Lima, Peru

ABSTRACT

In February 2021, Peru launched a vaccination campaign among healthcare personnel using BBIBP-CorV inactivated whole virus (BBIBP-CorV) COVID-19 vaccine. Two doses of BBIBP-CorV vaccine are recommended, 21 days apart. Data on BBIBP-CorV vaccine effectiveness will inform the use and acceptance of vaccination with BBIBP-CorV vaccine. We evaluated BBIBP-CorV vaccine effectiveness among an existing multi-year influenza cohort at two hospitals in Lima. We analyzed data on 290 participants followed between February and May 2021. Participants completed a baseline questionnaire and provided weekly self-collected anterior nasal swabs tested for SARS-CoV-2 by rRT-PCR for sixteen weeks. We performed multivariable logistic regression models adjusting for pre-selected characteristics (age, sex, exposure to COVID-19 patients, work in intensive care unit or emergency department, BMI, and exposure time in days). BBIBP-CorV vaccine effectiveness was calculated after the two-week post-vaccination period as (1-Odds Ratio for testing SARS-CoV-2 positive)x100%. SARS-CoV-2 was detected by rRT-PCR among 25 (9%) participants during follow-up (February-May 2021). Follow-up period ranged 1-11 weeks (median 2 weeks). Among cohort participants who were fully vaccinated the adjusted vaccine effectiveness against SARS-CoV-2 infection was estimated as 95% (95% CI 70%, 99%) and 100% (95% CI 88%, 100%) for those partially vaccinated. During the study period, vaccination of healthcare personnel with BBIBP-CorV vaccine was effective at reducing SARS-CoV-2 infections in the weeks immediately following vaccination. This information can be used to support vaccination efforts in the region, especially among those who could be concerned about their effectiveness.