By Aziza Atieno

The Coalition for Epidemic Preparedness Innovations (CEPI) and the Murdoch Children’s Research Institute (MCRI) have announced the launch of a global clinical trial investigating the impact of giving people reduced COVID-19 booster shots, as opposed to full doses as part of efforts to increase access to COVID-19 vaccines.

In the trials set to take place across Australia, Indonesia and Mongolia, as many as 3,300 adults will receive either a full or reduced dose of the Pfizer Inc.-BioNTech SE, Moderna Inc. or AstraZeneca Plc booster depending on their location.

This programme, funded by CEPI was launched following a recent statement by World Health Organization (WHO)  urging  the need for health equity in broader global access to COVID-19 vaccines across countries to achieve global public health goals.

“Over 10.4 billion doses of safe and effective COVID-19 vaccines have now been delivered worldwide, and the rollout of booster doses has dramatically ramped up in response to the spread of the highly infectious Omicron variant. However, despite this major progress, we continue to see a terrible chasm between rich and poor nations, with the vast majority of populations in low-income countries still waiting for their first dose, “said Dr Melanie Saville, Director of Vaccine Research & Development at CEPI in a statement.

“To prevent the further spread of this unforgiving virus and its troublesome variants, we need to achieve vaccine equity, fast. This new partnership will be key to showing us whether reduced booster dose shots could provide adequate protection against current and future variants, while also potentially showing that supplies of first doses to those in urgent need not be compromised.”

Contingent to the results from this trial, the data collected is expected to not only guide future COVID-19 vaccination strategies but also help understand whether administering half doses of half doses of COVID-19 has fewer side effects as compared to the full dose, which could improve the acceptability of vaccines. Additional data on administering heterologous (‘mix-and-match’) COVID-19 vaccine schedules will also be generated.

Professor Kim Mulholland, Murdoch Children’s Research Institute also mentioned the need to come up with smart strategies on how to best vaccinate communities with follow up booster shots, while considering the timings around the subsequent booster doses.

“We must do everything we can to ensure we have adequate supplies of vaccine to protect priority populations worldwide. Launching the fractional COVID-19 booster dose trial allows us to build on the expertise and stellar progress so far made by our partners at the Murdoch Children’s Research Institute (MCRI) to advance the fight towards ending this devastating crisis. Vaccinating the world as quickly as possible will enable a faster global recovery and ultimately benefits us all,” said Jane Halton, Chair of CEPI and Co-Chair of COVAX.

This form of administering reduced vaccine shots has previously been used to maximize global vaccine supply during outbreaks of Yellow fever and Polio.