The government’s advisory body on vaccines, ATAGI, is moving to expand the rollout of additional COVID vaccine doses.

ATAGI is considering third vaccine doses for children aged 12-15, and the organisation is also expected to make a decision regarding fourth doses this week.

But these shots were developed for a variant that is almost two years old, and experts say they’ll need to be updated eventually.

Vasso Apostolopoulos, a professor in immunology at Victoria University who has contributed to COVID vaccine research herself, said this news won’t be a massive game-changer for herd immunity.

Healthy children tend to experience mild symptoms, she said, and the virus has already spread around many classrooms this year, adding to natural immunity.

Meanwhile, additional shots have already been approved for those who need them most – immunocompromised people.

But now countries like Chile, Israel, Sweden and the UAE have started administering fourth doses of COVID vaccines to the general adult population.

Pfizer CEO Albert Bourla also called for governments to administer a fourth shot this week, and the company sought emergency authorisation for adults 65 and over in the US on Wednesday.

“The protection that you are getting from the third, it is good enough, actually quite good for hospitalisations and deaths,” Mr Bourla said.

“It’s not that good against infections.”

However, Professor Apostolopoulos pointed out that these vaccines were developed for the original strain of the virus in early 2020.

The virus has mutated more than 20,000 times since then.

“We need to prioritise new vaccines,” she said.

New variants require new vaccines. Photo: AAP

Administering fourth shots of existing vaccines will require a lot of money for an increasingly small benefit.

These doses could instead be prioritised for neighbouring countries that are still lagging on their first and second doses.

“Does the general population really need a fourth dose at this particular moment, or should we concentrate on giving these vaccines to those that are not vaccinated, in countries where only five per cent of the population is vaccinated?” Professor Apostolopoulos said.

New variants tend to mutate in unvaccinated populations, so diverting Australia’s future doses to developing countries is a win-win.

Professor Apostolopoulos said that instead of repeat doses of the same vaccine, Australians should anticipate an annual COVID vaccine that provides immunity against new strains.

Companies such as Pfizer and Moderna are already working on Omicron-specific vaccines.

The first of these are due to be available later this year.

“The flu vaccine that is available every year, that is actually different to the year before, because every year has new variants,” Professor Apostolopoulos said.

“So that’s what should happen – an annual COVID vaccine that includes the new variants.

“That’s what we should concentrate on.”