Decision on booster doses must be evidence-based

India-based data are needed that reveal whether the vaccines continue to protect against hospitalisations and death

The SARS-CoV-2 vaccination programme in India began on 16 January, this year. It has been close to eight months since the time individuals who were vaccinated early on received the second dose of the COVID-19 vaccine. This set includes healthcare and other frontline workers, followed by high-risk individuals, including the elderly. Countries such as the U.K., Israel, and the U.S. have started administering booster doses of vaccines, and this has led to the question of whether India should start considering booster doses as well.

For booster doses to be recommended as a policy decision, three criteria need to be met. First, it should be clear that the immunity offered by a vaccine wanes with time, and this results in an increase in the probability of breakthrough infections. Second, for a disease that runs a mild course in a majority of individuals, it should be evident that the lowered efficacy of vaccines with the passage of time is true not only for infection, but also for moderate-to-severe disease necessitating hospitalisation and/or causing death. Third, it is important to prove that the administration of a booster dose reduces the probability of such severe disease, thereby saving lives and reducing the burden on healthcare.