Norway-based Coalition for Epidemic Preparedness Innovations, or CEPI, has launched a new call for proposals to fund clinical trials evaluating the impact of reduced booster doses and third doses of COVID-19 vaccines. This approach could play an important role in stretching the global COVID-19 vaccine supply and increasing access to doses in underserved regions worldwide.

In particular, the research programme is inviting applications from individual organisations and consortia, including COVID-19 vaccine developers, to assess whether smaller doses of a single COVID-19 vaccine booster shot, as opposed to a full booster dose, would improve, broaden, and prolong the immune response following a primary series of COVID-19 vaccination, while also putting less strain on already constricted global COVID-19 vaccine supplies.

CEPI will make up to $25 million funding available as part of the call, with the intention to fund several clinical trials looking at dose-sparing booster shots for different COVID-19 vaccine candidates.

The funding will also support trials investigating whether a third, or additional vaccine doses, administered to immunocompromised people or other demographics, for whom the primary series of vaccine did not provide enough protection from COVID-19, could also be fractional, and still provide sufficient protection.