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Explainer
How successful is Australia's COVID-19 booster rollout and is it enough ahead of winter?
Health authorities are urging the 6.3 million eligible Australians who are yet to have a COVID-19 booster shot to book in their jab. But why have so many decided not to bother and how concerning is this as the days turn cooler and the Omicron BA.2 variant takes hold?
Published 21 March 2022 9:03pm
By Caroline Riches
Source: SBS News
Image: A nurse administers a person with Pfizer COVID-19 vaccine at Qudos Bank Arena vaccination clinic in Sydney, September 2021. (AAP / BRENDON THORNE)
Experts blame Australia's lagging COVID-19 booster take-up on confusion, a lack of awareness and, ironically, the success of our initial vaccine rollout.
As we settle in for our third year of the pandemic, Australians have been exposed to the virus like never before, with a recent rise in cases fuelled by the Omicron BA.2 variant. But experts say it's booster shots more than immunity from previous infections that will protect us through the winter.
The World Health Organization has said that while BA.2 is more contagious, it doesn't necessarily make people sicker. But a found that the variant is 40 per cent more contagious and is making hamsters sicker.
"Our multiscale investigations suggest that the risk of BA.2 for global health is potentially higher than that of BA.1," the study concluded.
So as the days turn cooler and people retreat indoors, how important is the booster rollout, where is Australia at compared to other countries, and is it enough to protect us from BA.2 and future variants? And can we expect a fourth booster before the winter is out?
How is Australia's booster rollout going?
Of the 18,793,478 Australians who are 16 and over and hence eligible to have received a third dose of a COVID-19 vaccine, 12,455,925 (66.3 per cent) have received one, according to .
Western Australia has the highest proportion of eligible residents triple jabbed at 85 per cent, followed by the ACT at 73.4 per cent, South Australia at 70.2 per cent, Tasmania at 68.6 per cent, Victoria at 67.5 per cent, the Northern Territory at 66 per cent, NSW at 62.2 per cent and Queensland at 61.1 per cent.
The number of Indigenous people to have received more than two doses of a vaccine stands at 179,137, which represents 49.9 per cent.
Meanwhile 92.8 per cent of aged care residents and 70.6 per cent of NDIS participants have received more than two doses.
Health authorities across Australia have been pushing for more people to get their booster shots — particularly the young, whose booster rates are lagging behind the general population.
Australians over 16 are able to book a booster dose if it's been three months or longer since their second dose of COVID-19 vaccine. If they have tested positive for COVID-19, they can have their next dose of the vaccine once they have fully recovered, or they can choose to defer it for up to four months after their COVID-19 infection.
Nathan Grills, Professor and Public Health Physician at the Nossal Institute at the Melbourne School of Population and Global Health, says after a successful first vaccine rollout last year, he believes we are "behind where we should be with our booster rollout".
He says it's important for people to remember that protection after a second vaccination goes down after five or six months.
"You still get some protection against severe disease but the protection against infection goes down towards zero. But the booster dramatically increases your protection against getting the virus by 50 per cent and it decreases your chance of getting severely unwell by 90 per cent," he told SBS News.
It also reduces the risk of long-term complications such as long COVID and and the risk of infecting your family, he adds.
Professor Catherine Bennett, chair in epidemiology within Deakin University's Institute for Health Transformation, said the fact we have seen booster rates rise among vulnerable groups is "good news" but says "it's really important" that we see rates increase across the population.
"The virus is spreading in the community and it will continue to spread. We do as a population have that broader immunity, which is good. But having that added protection of the booster can really make a difference," she told SBS News.
"If enough people are boosted across the population, that won't stop the virus but certainly help slow it down."
So why are so many Australians not getting boosted?
Professor Bennett says if there's any complacency among the population around booster shots due to the virus "not seeming too bad", this is only due to the efficacy of the first round of vaccines.
"We do have a lot of protection from the first round of Omicron and that is what has made Omicron a very different looking virus," she said. "If Omicron had come around in 2020 it would have looked no different to the other infections at the time probably, and we would have had a lot of people in hospital. It would have been devastating. So it shows how well the vaccination works."
Professor Grills said he's "surprised by the lack of awareness around the importance of the booster", which he blames on poor marketing and communication.
He believes some people remain unaware of when they should get their booster, or wrongly believe that a previous infection means they are already protected.
"The communication campaign has really gone really quiet on this. We're not doing well in getting the message out there, particularly to young people," he said.
"We need targeted messages. There needs to be much more attention in the media and through advertising that boosters are key."
Health authorities have tried to encourage more young Australians to get their COVID-19 booster shots, with the age group lagging behind in the rollout. Source: AAP / JOEL CARRETT/AAPIMAGE
So how does Australia's booster vaccine rollout compare to other countries?
Available data looks at the percentage of a nation's entire population rather than its eligible population that's boosted, with 18.5 per cent of the global population having now received a third coronavirus vaccine, according to .
Australia compares favourably, with 48.3 per cent of its total population boosted.
Chile is currently at the top of world rankings when it comes to its booster rollout, with 77.4 per cent of its total population having received a third jab. It is followed by Singapore, with 69.3 per cent of its total population boosted, Italy with 63.6 per cent, and Denmark with 62.1 per cent.
Some of the lowest rates of booster take-up are in India (1.4 per cent), Bangladesh (3.5 per cent) and Russia (8.7 per cent).
Higher levels of third doses in some high income countries are due to an earlier rollout of the first and second vaccines, which had made residents available for booster shots earlier.
Professor Bennett says the rise in booster levels is now "tapering off" in many countries, including Australia, but a correlation between booster rates and death rates is becoming stark.
Hong Kong, which currently has the (more than 260 deaths per million people, compared to Australia's current rate of 6.4) has a low booster rate of 29.6 per cent.
Professor Bennett blames Hong Kong's booster struggle on its successful COVID zero strategy, which fuelled complacency. But she says it proves how vital boosters are.
"Hong Kong has a high death toll. That's the cost laid down in front of us unfortunately. For the countries that have high booster take-ups, we have a very different picture."
She offers Denmark as an example. "Their hospitalisations remain in check and a lot of that is to do with their higher rates of vaccination."
Empty coffins are delivered to a funeral services shop and funeral parlours in the Kowloon district of Hong Kong. A funeral industry representative on 16 March told local media the soaring death toll due to COVID-19 had seen a crunch in the city's coffins supply. Source: Getty / ISAAC LAWRENCE/AFP via Getty Images
So with a mediocre booster rate, what can we expect this winter?
We know that winter can lead to a greater spread of infection as people move indoors. But the very high BA.1 infection rates and the resulting immunity should protect us against a rapid rise in BA.2 infections, experts say.
But they add that boosters offer even better protection against new variants than a previous infection.
"The vaccine provides the protection that getting Omicron may not provide given the lineage the variants come from," Professor Grills said. "Omciron comes from a very different lineage to Delta. An infection will give you protection against that one variant and some protection against other variants, whereas the booster will give you protection more widely across all the types of variants and sub variants that may arise.
"It's a combination of the vaccine and previous infection that is going to increase your immunity."
Professor Bennett says the layer of natural immunity combined with the booster should protect us well against future variants.
"It starts to make it less likely that we will see a variant come along that we have no protection against. Our immune systems are learning globally, and that's taking some of the sting out of it."
What variants can we expect to emerge?
While no one knows what variants are around the corner, Professor Grills believes we are more likely to have less dangerous variants because ultimately, a virus doesn't want to kill its host who it relies on to keep on spreading.
"I'm of the opinion that we are more likely to have less virulent and more infectious variants. They tend to dominate the viral landscape because they're much more effective at spreading. I'd be confident that's the way we'll go with future variants."
"But there's still a significant chance that the next variant will be more virulent and as infectious as the current one and that would be a dangerous situation if you're not boosted," he said.
Dr Deborah Cromer leads the Infection Epidemiology and Policy Analytics Group at the Infection Analytics Program at the Kirby Institute, UNSW. She believes the winter will depend on what variant emerges and its virulence — and she doesn't agree that future variants are more likely to be mild.
"If you get a new variant that is highly transmissible but extremely mild, that would be excellent, " she said.
"If you get a new variant that is highly transmissible but more severe that would be worse, and I think that will play a bigger factor than the season.
"COVID is still very good at spreading. But what the virus doesn't want is for its host to be so sick that it can't transmit for the entire infectious period because the host is isolating. As long as there's a period during which it can spread, I don't think the severity is of huge consequence to the virus and therefore I don't think it has to evolve towards milder symptoms. I think the symptoms are irrelevant to the virus."
When will we see fourth boosters rolled out?
found that while booster shots of the Pfizer and Moderna vaccines remained highly effective against moderate and severe COVID-19 for about two months after a third dose, their effectiveness declined substantially after four months, suggesting the need for additional boosters.
While the booster vaccine was 91 per cent effective in preventing a vaccinated person from being hospitalised during the two months, protection after four months fell to 78 per cent. After more than five months, vaccine effectiveness fell to roughly 31 per cent (but researchers noted that estimate was “imprecise" due to a lack of data).
In Australia at present, (though the Australian Immunisation Register considers them fully vaccinated after three).
Professor Grills says it will be interesting to see what vaccines come along over winter, especially given the talk around potential "universal vaccines" that protect against all variants. Either way, it won't be long before we're all receiving our fourth booster, he says.
"In six months time the majority of the population would have had their third dose more than six months ago and immunity would have waned significantly," he said.
"It may not be mandated but it definitely will be available to the general public in the next six months and should be available for people in high-risk settings and frontline health workers sooner than that — in the next two or the months, I would have thought."
Dr Cromer says at this point in our journey, boosters remain our greatest defence.
"What we are seeing worldwide is vaccination and boosting is extremely effective in preventing severe disease and so if we're looking at protecting ourselves and society against really severe disease, I think the more people that can get boosted the better.
"Even across new variants, even after a reasonably long period of time, vaccines are still the best thing that we have to combat people ending up in hospital. Therefore boosting is really important."
