A Phase 2 clinical trial of Covid-19 booster shots has begun registering adult participants in the US, the National Institutes of Health (NIH) announced. The clinical trial seeks to understand if different vaccine regimens can strengthen the immune system in adults who already have the primary vaccination series and a first booster shot.

“We are looking beyond the Omicron variant to select the best strategy to protect against future variants. This trial will help us understand if we can use prototype and variant vaccines alone or together to shift immune responses to cover existing and appearing Covid-19 variants,” Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases (NIAID), said