The government says it will continue to listen to its advisory panel of medical experts about Australia’s COVID-19 vaccine rollout amid calls for Australia to push for greater access to the Pfizer and Moderna vaccines.
Some infectious diseases doctors and immunologists have raised concerns about whether the Oxford University vaccine will be effective enough to achieve herd immunity, with debate over its efficacy rate.
According to details on its phase-three trials published by the university last November, it trialled two different dose regimens that produced different results.
When people received a half dose of the vaccine, followed by a full dose booster, the efficacy rate was found to be 90 per cent.
When they received two full doses, it was 62 per cent – a figure that concerns some medical experts.
Overall, when the two results are combined, the efficacy rate is 70.4 per cent.
The Australian and New Zealand Society for Immunology’s president Dr Stephen Turner said while he agreed the vaccine had many benefits, he thought the government should also look at bolstering supplies of the Pfizer and Moderna vaccines, which have higher efficacy rates.
“It makes a lot of sense to push ahead with the Pfizer and Moderna vaccines and get our hands on as much of that as possible,” he said.
“I think the [vaccine rollout] plan is robust but it is being able to … pivot towards getting more of [those] vaccines, I think that makes a lot of sense.”
There are no questions about the safety of the AstraZeneca option or the need for a vaccine.
Earlier in the week, experts told the ABC the strategy to vaccinate the most vulnerable Australians with the Pfizer drug and the rest of the population with the AstraZeneca vaccine “makes sense” and having ongoing access to the latter was a “huge advantage”.
As for whether Australians would receive a half dose first followed by a full dose, leading to the higher efficacy rate, is a decision for the Therapeutic Goods Administration that is considering the approval of the vaccine.
A spokesperson for Health Minister Greg Hunt said the government’s decisions were “being driven by the combination of scientific advice from medical experts” on the advisory body chaired by former chief medical officer Professor Brendan Murphy.
“The AstraZeneca/Oxford vaccine clinical trials demonstrated the vaccine is generally well tolerated and effective at preventing symptomatic COVID-19 and that it protects against severe disease and hospitalisation,” the spokesperson said.
“The TGA is currently evaluating the safety, quality and efficacy of the AstraZeneca/Oxford vaccine under its provisional approval pathway.
“A decision to provisionally approve the vaccine will be made following rigorous assessment of all the available data.
“Further detail on vaccine efficacy is being collated now and includes data from many millions of vaccinations across countries that have used early authorisations, such as the US, Canada and the UK.”
Chief medical officer Paul Kelly said he, and everyone else, should listen to the experts advising the government.
“They’re hand-picked experts on these matters,” he said.
“They held us in very good stead for many, many years.
“Not only in COVID vaccination, but all of our vaccination programs that we have rolled out and the coverage is very high.”
‘We need to pivot’
Monash University Infectious diseases physician Dr Michelle Ananda-Rajah agreed with Dr Turner that the government needed to work to secure more doses of the Pfizer and Moderna vaccines.
“We need to pivot our strategy,” she said
“This is not about saying that we don’t need vaccination, we absolutely do need vaccination – we all accept that the vaccine is our exit strategy out of this.
“It’s really about just ensuring that we provide for Australians the best possible vaccine and at the moment the data is telling us that the Moderna and Pfizer vaccine are the most effective.”
Australia has secured 10 million doses of the Pfizer vaccine, which will inoculate five million people, starting with frontline quarantine and health workers.
“They are being given to high risk people,” Dr Ananda-Rajah said.
“The issue though is that the rest of the country is going to be offered a lower efficacious vaccine – the AstraZeneca – and that’s just not going to confer herd immunity at a population level, we just don’t believe that based on our current data.”
A spokesperson for AstraZeneca said the TGA was still considering the data and the decision was up to the regulator.
The spokesperson said AstraZeneca always believed more than one vaccine candidate was needed to address the global health emergency.