The reputation of the AstraZeneca COVID-19 vaccine has taken a beating in the past few months, with links to very rare blood clots and changing health advice limiting its use to younger Australians.
But as both medical and governmental authorities say - the jab is still among the best bets Australians have when it comes to warding off serious disease, hospitalisation and death associated with COVID-19.
So what's happening with the shot that was once billed as the “workhorse” that would vaccinate most of the country, and where are we going from here?
Here's what you need to know.
What’s changed recently?
The AstraZeneca vaccine is now only recommended for Australian adults over 60, , following fresh advice from the Australian Technical Advisory Group on Immunisation.
Those who’d already received the first dose are still being urged not to cancel their appointments for the second dose and show up - the Department of Health says almost all of the few cases of blood-clotting reported to date have occurred after the first dose of the vaccine.
“People who have had their first dose without any serious side effects can be confident in getting their second dose,” it advises.
The reason behind the change was based on an assessed greater risk for younger people of the blood clotting disorder thrombosis and thrombocytopenia syndrome, or TTS.
“It is important to appreciate however that this may be subject to further changes in the future, in either direction, as the situation around us continues to evolve,” said Paul Griffin, the director of infectious diseases at Mater Health Services in Sydney.
What's its future in Australia?
The government has agreed to buy 53.8 million doses of the AstraZeneca vaccine, and plans were made earlier this year to manufacture 50 million more onshore.
The vaccine will continue to be available for those over 60, but it’s a far cry from the government’s original plan to use it to inoculate most of the population.
Professor Jill Carr, a virologist with the College of Medicine and Public Health at Flinders University, said limiting the vaccine to over-60s will affect Australia’s ability to achieve a good level of community immunisation quickly.
“AstraZeneca was our initial major supplier,” she said. “However, it seems the government has alternative arrangements in place to cover this short-fall in supply for under 60s.”
Pfizer is now set to play a bigger role in Australia's rollout.
The coordinator of Australia's COVID-19 vaccine rollout, Lieutenant General John Frewen, said on Monday Pfizer supplies are being "carefully managed" .
Officials say the benefits of getting the AstraZeneca shot for people aged over 60 far outweigh the risks.
Why can’t we just scrap it?
One reason is that, despite the very low blood-clotting risks, the AstraZeneca jab has been lauded for providing a high level of protection against death and hospitalisation associated with COVID-19.
To put that in perspective, the risk of dying from TTS is about one in 2 million doses - about the same as death after being struck by lightning.
As , you’re more likely to die walking down the street, by drowning, or in a car accident.
“When you fully appreciate how small the risk of TTS is, the decision to have the AstraZeneca vaccine to protect yourself and others becomes a much easier one to make,” said Hassan Vally, an associate professor from La Trobe University's Department of Public Health.
Do we have enough Pfizer?
Another reason we can't ditch AstraZeneca is that we don’t have enough of the Pfizer vaccine for the whole population - yet.
So far, Australia has ordered 40 million doses of the Pfizer vaccine, which is also a two-dose shot. Half of those have been promised to be delivered in the fourth quarter of this year.
Pfizer vaccine supplies are currently limited and we’re not likely to get the Moderna or Novavax jabs until much later this year.
“Unfortunately, the federal government put most of their eggs in the AstraZeneca basket, and this is now becoming a major problem,” said Adrian Esterman, the chair of biostatistics at the University of South Australia.
Professor Julie Leask, a professor of nursing and midwifery at the University of Sydney who focuses on infectious disease and immunisation, said demand is likely to increase for the Pfizer vaccine in the coming weeks and months.
Health advice around the AstraZeneca shot in Australia has been updated yet again. Source: EPA
“Until we get enough supply, some may not be able to access Pfizer when they want to, particularly in the younger age groups,” she said. “This will intensify during outbreaks [of COVID-19] when we see a surge in vaccine demand. For the most part, we hope that most jurisdictions can manage the extra demand until we see a ramp-up in supply later in the year.”
What're other countries doing?
Countries have responded differently to how they plan to administer the AstraZeneca vaccine - whether by age or sex, or by banning its use entirely.
In the United Kingdom, the AstraZeneca jab is available to Britons over 40, while South Korea has limited its use to those over 30.
There’s now no age limit in Germany after the country lifted a previous restriction banning its use to those under 60.
Chile has recently raised the minimum age at which men can receive the vaccine to 45 years of age from 18, bringing it in line with its over-45s only restriction imposed for women.
Like Australia, Italy has recently stopped administering the jab to those under 60. The Italian government has announced younger Italians who’ve already been given their first dose of AstraZeneca will get a different shot for their second. Spain has also limited the use of AstraZeneca to those over 60.
Denmark in April became the first country to stop using the vaccine entirely after initially suspending its use, though authorities are now being asked by the government to reconsider the move. Norway has also removed the AstraZeneca jab from its program.
