As Australia scrambles to find a ‘Plan B’ for its COVID-19 vaccine strategy, the medical experts who made the shock decision to recommend against the AstraZeneca vaccine for under 50s have unpacked the reasons why.
After the UK issued advice that the AstraZeneca vaccine not be offered to under 30s there were few who would have picked Australia going even further and excluding under 50s on their 2021 bingo card.
But Professor Allen Cheng, an executive member of the Australian Technical Advisory Group on Immunisation (ATAGI) that advises the Morrison Government on the immunisation program for COVID-19 vaccines, has explained the reasons overnight.
“So how did we come up with 50 years? And why did the UK pick 30 years as a threshold?” Professor Cheng said.
“If there was a lot of COVID about, then the benefit in preventing COVID would outweigh the risk for almost all adults, except for very young adults. This is pretty much the situation in the UK at the moment.”
But that’s not the case here in Australia where COVID-19 is largely under control and confined to hotel quarantine facilities.
“In Australia, we don’t have COVID in the community at the moment, but we recognise that the risk of incursion is ever present. So the balance of the risks and benefits are different,” Prof Cheng said.
In other words, if the risk of catching COVID and dying is negligible in Australia, the risk of taking a vaccine that in rare cases could cause a blot clot is a higher risk.
“There are a few caveats here. If we could work out who did and who didn’t get this clotting condition, we might be able to advise younger people better about their personal risk,” Prof Cheng said.
And he admits if there is a major outbreak that could change the risk equation again.
“If we had a large outbreak, then this risk-benefit analysis would change and we’d have to reconsider this advice. The risk-benefit balance would also be different in countries with even larger outbreaks than the UK.”
Experts stress that the advice to under 50s is just that – it’s not an order and they are not telling people not to take the AstraZeneca vaccine if they choose to do so.
“We also carefully used the word ‘prefer’ (Pfizer over AstraZeneca) in younger people. We respect patient autonomy – that people have a choice about the vaccines and treatments they get,” Prof Cheng said.
“If a younger person said that they were happy to take a one in 200,000 risk of clotting for the benefit of getting protected from COVID earlier, then as long as this was an informed decision, we should respect that choice.”
For people who have already taken the first AstraZeneca jab Prof Cheng said there wasn’t much to worry about.
“What if you’ve already had your AZ vaccine? The good news is that 199,999 out of 200,000 people won’t get anything more than a sore arm and a fever for a day or so, and you’ll be protected against getting COVID after a few weeks,’’ he said.
“But if you get severe persistent headaches or other unusual symptoms between four and 20 days after vaccination, seek medical attention.”
This is different to the common side effects after vaccination, which usually only last a day or so.
What is our Plan B?
For now attention has turned to the ‘Plan B’ after the decision largely knocked out the use of the AstraZeneca vaccine for under 50s.
“The other obvious question is about alternatives to AZ. I’m not privy to the discussions, but I do know that the Australian government have been in constant communications with vaccine manufacturers,’’ Prof Cheng said.
“It’s no secret that there is global competition for available vaccines, and we have secured enough Pfizer for 40 per cent of the population over the remainder of the year.
“We have access to some more vaccines via COVAX, and Novavax hopefully coming later in the year subject to regulatory approvals and supply.
“There’s no question that this decision will slow things down – having onshore capacity to produce vaccine is very valuable.
“So over the next few days, Commonwealth and state governments will be working out how the program will look in the coming weeks and months. But because we’re thankfully not dealing with ongoing COVID outbreaks, we can make this choice to take a safer path.”
Chief Medical Officer Paul Kelly said he was concerned the debate could hit public confidence in the vaccine program.
“Of course something like the announcements overnight can affect vaccine confidence,” he told the ABC.
“But the important thing is for the Australian public to know that as soon as we’ve known something, as soon as our expert advice from the ATAGI group gives us the guidance on immunisation, we went out and informed the public.
“We’ve made this preference for not using AstraZeneca in the under 50s on the basis of that safety concern but I would really urge people to make sure that they are lining up when it’s their turn.”
Professor Kelly said “nothing is off the table”, suggesting that the government was considering a deal with Moderna to redress vaccine shortfalls.
“We are looking at all of those options right now. We know that Novavax – we have 51 million doses on order – is not yet approved by the TGA,” he said.
“I do really want to stress that for people in those priority groups right now, people in aged care residences, people over the age of 70 or 80, AstraZeneca is perfectly safe.”