A global vaccine trial led by the Murdoch Children’s Research Institute in Melbourne will determine if reduced doses of COVID-19 booster shots are still effective.

Researchers hope that a smaller dose for a booster shot could make the experience more comfortable for many people and help global vaccine supplies.

“While fractional doses could provide the opportunity for great savings for countries, they are also likely to produce fewer side effects, which will improve the acceptability of booster doses,” said Professor Kim Mulholland in a statement provided to The New Daily.

The COVID-19 vaccines being trialled in smaller doses are those made by Pfizer, Moderna and AstraZeneca.

The clinical trial is partially funded by the Coalition for Epidemic Preparedness Innovations (CEPI), with additional studies taking place in Indonesia and Mongolia, where Professor Mulholland is currently located.

All three countries are regional leaders in immunisation.

If reduced booster doses are found to be effective and safe, it would also help the global vaccine rollout because there would be more to go around.

Professor Mulholland said that this “fractionalisation” of vaccine doses isn’t new – it has been used during polio and yellow fever outbreaks to maximise the global vaccine supply.

Not only would this free up manufacturing capacity for developing countries to receive their first and second vaccine doses, but it would also see an even greater availability of booster shots in countries where they’re needed.

“To prevent the further spread of this unforgiving virus and its troublesome variants, we need to achieve vaccine equity, fast,” said Dr Melanie Saville, director of vaccine research and development at CEPI.

“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.”

To that end, all data from the trial will be made public in open-access journals, so the findings can be shared as widely as possible.