Why we may not be offered a Covid fifth jab anytime soon and people who least benefit

The jury is out on whether an extra Covid booster shot is needed for most Australians, especially for one sex and age group. This is why.

Healthy Australians may not be told anytime soon to get additional Covid shots as scientists weigh up the need for, and risks of, vaccine boosters against potential benefits — especially for young males.

Top Covid researcher Professor Jodie McVernon told the Herald Sun it was possible boosters would be offered only to the most vulnerable Australians rather than rolled out widely in future.

“It’s going to be, most likely, like other infectious diseases such as flu, giving vaccines to the people at highest risk of severe outcomes but it’s still a work in progress … still being resolved,” the director of epidemiology at Melbourne’s Doherty Institute said.

For at least one group — 12 to 15 year-old males — the risk of vaccine booster side effects could outweigh potential benefits, Prof McVernon said.

“Vaccine side effects have been observed and the benefits of vaccination — given that Covid is very unlikely to be a severe disease in that group — became much more marginal, of understanding what the cost-benefit was,” she said.

“So whether there is an ongoing recommendation for vaccination and booster vaccination, my own sense is … boosters will be most indicated and most cost effective in older individuals or individuals with risk indications, who are more likely to get severe disease.”

An expert says future Covid waves in Australia are likely to be less concerning than in the past, as the population develops ‘hybrid immunity’. Picture: David Crosling

It follows an Australian Technical Advisory Group on Immunisation (ATAGI) decision late last year not to recommend a fifth Covid jab, even as case numbers soared across the country amid a sweeping fourth virus wave.

It was believed that advice could change early this year, but is yet to.

Asked by the Herald Sun in late December if people were being personally notified if and when their fifth jabs were due the Australian government responded only: “People should stay up to date with Covid-19 vaccinations as they provide optimal protection against severe disease and hospitalisation”.

Professor McVernon said Australia was working with the World Health Organisation (WHO) and looking to other nations to see what decisions were made on the need for boosters.

“It is an open question globally of ‘are boosters needed and if so, how often and who gets them? What’s the cost-benefit’?” she said.

Professor McVernon said vaccines had done “an amazing job” of minimising severe disease and deaths but could not “switch off Covid”, and mutations were continually emerging.

And future Covid waves in Australia were likely to be less concerning than in the past, as the population developed “hybrid immunity” through past infections and vaccinations, she said.

“The thing we’re learning — and looking at the data seems to be the case — is that with each incremental exposure via the vaccine or infection, that there’s actually an incremental build of immunity … we expect to see more dampened waves of infection over time because population immunity is building up. Unless there’s a major immune escape variant, we expect to see less big, dramatic waves coming through and them being smaller and shorter and further apart,” Professor McVernon said.

“But it depends to some extent on when variants emerge and when the population was last exposed and when the last vaccine program was administered … so it’s a question of what’s the timing and frequency, if we’re going to give vaccines, and who we would give them to.”

A top scientist says China’s massive Covid outbreak could give the virus more opportunity to evolve. Picture: AFP

It comes as another top scientist this week slammed Australia’s Covid response, saying it was “as offensive as it is ridiculous” to accept the virus “as fact of life”.

Burnet Institute chief Professor Brendan Crabb warned “virtually every family” would be affected in the state’s current Covid wave and even those who had the virus recently risked reinfection because of the ability of mutant strains “to get around” prior immunity.

“As a result, most/all are susceptible to reinfection after a relatively short period (months),” Professor Crabb said.

“Infection is dangerous for everyone, be cautious no matter what your prior exposure … please don’t think you’re bullet proof if you’ve been infected before — far from it.”

Professor Crabb, who is the director and chief executive officer of the Melbourne-based Macfarlane Burnet Institute for Medical Research and Public Health also said on Twitter China’s massive Covid outbreak gave the virus more opportunity to evolve and was reason for worry, but not the chief worry in Australia.

“It would be a mistake to think that if we keep virus from entering from China that we are OK, that that is where the danger lies,” he said.