Effectiveness of BBV152 vaccine against SARS-CoV-2 infections, hospitalizations and deaths among healthcare workers in the setting of high delta variant transmission in New Delhi, India

Abstract

AbstractBackgroundDelta variant transmission resulted in surge of SARS CoV-2 cases in New Delhi, India during the early half of year 2021. Health Care Workers (HCWs) received vaccines on priority for prevention of infection. Real life effectiveness of BBV152 vaccine against severe disease including hospitalization and death was not known.ObjectiveTo estimate effectiveness of BBV152 vaccine among HCWs against SARS CoV-2 infection, hospitalization or deathDesignObservational studySettinga multi -speciality tertiary care public funded hospital in New Delhi, India.Participants12,237 HCWsInterventionsBBV152 vaccine (Covaxin, Bharat Biotech limited, Hyderabad, India); whole virion inactivated vaccine; two doses four weeks apartMeasurementsvaccine effectiveness after receipt of two doses of BBV152 protecting against any SARS CoV-2 infection, symptomatic infections or hospitalizations or deaths, and hospitalizations or deaths.ResultsThe mean age of HCWs was 36(±11) years, 66% were men and 16% had comorbidity. After adjusting for potential covariates viz age, sex, health worker type category, body mass index, and comorbidity, the vaccine effectiveness (95% Confidence Interval) in fully vaccinated HCWs and ≥14 days elapsed after the receipt of second dose was 44% (37 to 51, p<0.001) against symptomatic infection, hospitalization or death due to SARS CoV-2, and 61% (37 to 76, p<0.001) against hospitalization or death, respectively.ConclusionsBBV152 vaccine with complete two doses offer a modest response to SARS CoV-2 infection in real life situations against a backdrop of high delta variant community transmission. Efforts in maximizing receipt of full vaccines should be invested for HCWs, who are at higher occupational risk for infection.