COVID-19 immunity doesn’t seem to be working well enough to manage the pandemic, says Burnet Institute head

As COVID-19 drives Australia’s mortality rate higher, experts are questioning whether the Government’s approach to the pandemic remains appropriate.

In 2022, Australia was about 16% more deadly than average. Early data from the Australian Bureau of Statistics shows that there were 19,986 “excess deaths” to the end of September: that is, nearly 20,000 more deaths than would be expected over the year.

The main culprit is COVID-19, both directly – with around 12,000 deaths in 2022 – and indirectly, through an overwhelmed hospital system.

As a new variant takes off around the world, the disease doesn’t seem to be getting any less virulent. So: beyond vaccination, are there other ways we should still be trying to control COVID-19 in 2023?

Professor Brendan Crabb, director and CEO of the Macfarlane Burnet Institute for Medical Research and Public Health, says that encouraging vaccine uptake as well as better ventilation, masks and more available tests could all drive down hospitalisations and deaths.

“Governments need to spend the money to make them available, businesses need to spend money to make them available. And together, they will knock transmission down,” says Crabb.

The current strategy, in Crabb’s opinion, relies too heavily on immunity from vaccination and prior infections.

“At the moment, we have an ‘infection is okay, and healthy people protect the vulnerable’ strategy. And I don’t think that’s working,” says Crabb.

“I think public health officials are still hoping, ‘well, maybe this will be our last wave’. They were hoping that the last one, and the one before, and the one before. It’s pretty unlikely now that that’s going to work.”

While reinfection does induce some immunity, Crabb believes it’s unlikely to be enough to let the virus taper out.

In November, the Kirby Institute’s blood sample survey indicated that 65% of Australian adults had antibodies which meant they’d been infected with COVID-19.

Because these surveys generally miss about 15-20% of past infections, the researchers estimated that roughly 80% of the Australian population had been infected with COVID-19 at that point: a number both significantly higher than official test results, and a number that means a large proportion of current cases must have had COVID-19 before, even if they weren’t aware of it.

“In the UK, or the US, or France, where exposure to infection is even greater than Australia’s, they’re going through a big wave now. So, clearly being previously infected is no great impediment to getting infected again,” says Crabb.

“I’m not saying immunity to infection doesn’t work – it does work. But it just doesn’t work well enough. And it’s an argument for why we need a strong vaccine, plus other things.”

What are those other things?

“The most important thing is a reality check, delivered by our leaders to say, ‘actually, we’ve got a big challenge on our hands. We want to reduce transmission’,” says Crabb.

“And the good news is we have a suite of very effective, non-restrictive tools to do that.”

There are four broad controls, according to Crabb: vaccination, clean air, masks, and testing.

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Read more: Borders and boosters: what tools should we really be using against COVID in 2023?

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While, obviously, not completely effective, up-to-date vaccination does still reduce transmission of COVID-19. A recent study in Nature Medicine found that, among a prison population, vaccination reduced the risk of transmitting COVID to someone else by 22%. Immunity from prior infection led to a 23% lower risk of transmission, and vaccination and prior infection combined made people 40% less likely to transmit COVID-19.

The Australian Technical Advisory Group on Immunisation (ATAGI) still doesn’t recommend a fourth dose of vaccine for those under 30, or widely recommend a fifth dose. This means that people who received boosters late in 2021 or early in 2022 still aren’t eligible for the Omicron-targeting bivalent vaccine.

This is different to countries like the US, where all adults are eligible for a bivalent booster.

“They [ATAGI] must have a risk benefit analysis that they need to be quizzed on,” says Crabb.

“My own view is that policymakers, of which ATAGI is contributing, are way too comfortable with infection. That’s my major criticism.”

Currently, ATAGI’s recommendation that under-30s remain ineligible for a fourth dose is that “it is unclear whether the benefits outweigh the risks in this population”, according to their website.

“I do know and respect the individuals [in ATAGI]. I’m not in the room with them. But it does, from one step away, seem quite perplexing to me,” says Crabb.

Regulations on air ventilation and masks, meanwhile, can also lower the risk of transmission. Some countries have installed monitors in schools, for instance, to ensure CO₂ levels don’t exceed 800 parts per million – generally considered the mark of a well-ventilated room. N95 or similar masks, while expensive, are also the most effective masks to reduce transmission.

Finally, “testing is absolutely crucial,” says Crabb.

“Because if you’re positive, you can take extra care to either stay away from people, or to wear a mask, or whatever you can do to prevent transmitting the infection.

“But also, you can get treated. You can’t get treated unless you’re diagnosed. And in fact, you can’t get treated effectively unless you’re diagnosed early.”

Treatments like Paxlovid have reduced mortality in severe COVID cases.

The good news is that, while waiting for infection-based immunity to kick in seems unlikely to work, there are better tools on the way.

Crabb believes that better treatments could be appearing in under 12 months, while next-generation vaccines and more effective air purifiers won’t be far behind.

“The tools we’ve got now will not be the tools we will have in six to 12 months. We’ll have better ones.”

Correction, 11 January 2023: The original version of this article had a comment in Paragraph 13 which was inaccurate. Cosmos has updated the article with a new comment from Professor Crabb.