A single COVID-19 vaccine dose does not seem to offer a significant protection against symptomatic or severe COVID-19 infection, noted a study conducted at Sir Ganga Ram Hospital in Delhi.

The study is based on COVID-19 infections among healthcare workers at the hospital between March 1 and May 31, 2021, during the second wave. Dr Ruma Satwik, the lead study author, stated that the study on vaccine effectiveness suggested that a single vaccine dose offered very little protection against symptomatic infections or any outcome of interest, i.e., risk of developing severe disease or death due to COVID-19. The incidence of symptomatic infection in healthcare workers who had been administered a single dose of the vaccine (21 days after getting the dose) was found to be 12.3%, compared to 13.9% among the unvaccinated healthcare workers. About 2% of the partially vaccinated participants developed moderate to severe disease and 0.7% needed oxygen therapy. On the other hand, 3.3% of the unvaccinated participants developed moderate to severe disease and 1.7% needed supplemental oxygen therapy… (ET Healthworld – TNN, August 18, 2021)