The country has ordered 20 million Pfizer vaccine doses
Australia said on Thursday that they now recommend people under 50 should get Pfizer's Covid-19 vaccine in preference to AstraZeneca's shot, a policy shift that it warned would hold up its inoculation campaign.
The move, a day after European regulators reiterated they had found possible links between AstraZeneca's shot and reports of very rare cases of blood clots, is a huge hurdle for Australia's vaccination program, which had relied on that vaccine.
Australia's Chief Medical Officer Paul Kelly told reporters the risk of clots was extremely low.
"It's only been found in the first dose of the AstraZeneca vaccine, usually within four to 10 days after that vaccine. But it is serious, and it can cause up to a 25% death rate when it occurs," he said.
Australia would advise health providers to only give a first dose of the AstraZeneca vaccine to adults younger than 50 when the benefit clearly outweighs the risks, he added.
Italy and Britain on Wednesday joined other countries in suggesting age limits for AstraZeneca's vaccine. But the European regulators reaffirmed the importance of that shot in protecting people against Covid-19.
Those who have already had a first AstraZeneca dose without any serious adverse events "can safely be given their second dose," Kelly said.
Prime Minister Scott Morrison said the updated advice will delay Australia's inoculation timetable, but it was too soon to say when Canberra would now vaccinate its adult population.
"There will be a recalibration of how the program will need to be adjusted," Morrison told reporters in Canberra.
Australia has ordered 20 million doses of the Pfizer vaccine and Morrison said Canberra was in talks to increase the order.
Authorities will continue to give the AstraZeneca vaccine to people over 70. Those over 50 who opt for the Pfizer vaccine will have to wait, the Australian government notified.
Australia had planned to use the AstraZeneca vaccine for the vast majority of its near 26 million population and expected to give all adults at least one shot by October.
But its immunization campaign was already heavily behind schedule.
It had pledged to administer at least 4 million first doses by the end of March, but could only deliver 670,000, with the government blaming the delay on supply issues in Europe.
It had been looking to ramp up the immunization effort, underpinned by plans to make 50 million doses of AstraZeneca vaccine in Australia, produced by CSL Ltd.
Australia began vaccinations much later than some other nations because of its few infections, which stand at just under 29,400, with 909 deaths, since the pandemic began.