Can Fractional Vaccinations Broaden COVID-19 Immune Responses

The Norway-based Coalition for Epidemic Preparedness Innovations (CEPI) announced a Call for Proposals on October 11, 2021, to fund clinical trials evaluating the impact of reduced booster doses and third doses of COVID-19 vaccines.

In particular, the CEPI research program is inviting applications from individual organizations 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.

Administering smaller vaccine shots—also known as fractionation—has previously been used to maximize global vaccine supply during Yellow fever and Polio outbreaks.

Currently, there are over twenty COVID-19 vaccines in use globally, with about 100 vaccine candidates conducting clinical trials, according to GAVI.

CEPI will make up to the US $25m funding available as part of the Call to fund several clinical trials looking at dose-sparing booster shots for different COVID-19 vaccine candidates.

The findings from the CEPI-funded trials are expected to provide essential data to inform the public health and scientific community, including groups like the National Immunisation Technical Advisory Groups and the WHO Strategic Advisory Group of Experts on Immunization on the potential merits of vaccinating people with fractional doses of COVID-19 vaccine.