Prevalence and predictors of SARS-CoV-2 breakthrough infection among recipients of 2 doses of COVAXIN: a retrospective analysis: Prevalence and predictors of breakthrough SARS-CoV-2 infection following COVAXIN
Introduction Vaccines against SARS-CoV-2 have been an important tool in combating the ongoing COVID-19 pandemic and the Indian-made COVAXIN (BBV152) is one of the most important of them. However, research regarding its short-term protection against the disease is still scarce. Objectives To find the proportion of beneficiaries that develop Covid-19 following 2 doses of COVAXIN vaccine in a vaccination centre from Darjeeling, West Bengal To find the risk factors for SARS-CoV-2 infection following 2 doses of COVAXIN vaccine Materials and Methods A retrospective longitudinal study was done among adults receiving the first dose of COVAXIN at the vaccination clinic of North Bengal Medical College from the 1st to the 31st of March 2021. The study was carried out from July to November 2021 and all of the recipients were interviewed via telephone. Results Of the 612 recipients whose responses were analysed, most were men, lived in rural areas, with mean age of 47.4±16.8 years. Most of the respondents (32.8%) were government servicepeople. Of them, 47 (7.7%) developed COVID-19 after second dose, although none were hospitalised or died. Multivariable analysis found that increasing the gap between the two doses was significantly associated with a higher odds of breakthrough infection after the second dose (AOR 1.013, p-value = 0.032) Conclusion While effective in preventing COVID-19 and the severity of breakthrough infections, protection offered by two doses of the COVAXIN wanes with time and increasing the gap between the two doses might lead to a higher risk of developing COVID-19 after the second dose.