It is "unlikely" all Australians will have had their second dose of the coronavirus vaccine by the end of October, with the possibility the initial rollout could even stretch into 2022, Health officials have conceded.
In the first concession the October target was out of reach due to delays in the rollout, Health secretary Brendan Murphy played down the significance of the October target, which government ministers had still been touting as the end of the rollout as recently as Wednesday.
Both the Pfizer and AstraZeneca vaccines for coronavirus being used in the Australian rollout require two doses, with a three-week gap for the Pfizer vaccine and a 12-week gap for the AstraZeneca vaccine, which makes up the bulk of Australia's program.
Professor Murphy said it was "semantic" when questioned about when the end date of the rollout would be if not October, pointing to clinical data showing people would be largely protected from the virus after the first dose of the vaccine.
"We don't know if we will be able to deliver two doses by the end of October," Prof Murphy said.
Australia's vaccine rollout is less than three weeks old and already plagued by delays, with 125,000 people receiving the first dose of their vaccines.
Delays have been attributed to issues with importing Pfizer and AstraZeneca vaccines from Europe, where manufacturers have had both production delays and had vaccines blocked from leaving the European Union.
The government had originally said 4 million doses of the vaccine would be administered by the end of March but had to start backing away from the promise not long after it was first made.
Prof Murphy said it was "impossible to predict" when the 4 million figure would be reached, citing the unknown capability of CSL to increase its onshore manufacturing of the AstraZeneca vaccine and the uncertainty around the rate imported vaccines would enter the country.
The administration of the vaccines had also been slower than planned, Prof Murphy telling a Senate committee the situation in aged care homes was more complex than first thought, leading to fewer doses injected each day.
The government had previously promised all Australians would be offered full vaccination against coronavirus by the end of October, but Prof Murphy said modelling had been done when it was assumed there would be a four-week gap between the first and second doses of the AstraZeneca vaccine, not the 12-week gap now clinically recommended.
The 12-week interval between doses had been foreshadowed since the United Kingdom started extending the gap as part of a bid to vaccinate more of the population more quickly, but has been certain since the Therapeutic Goods Administration approved the AstraZeneca jab on February 16. Officials told a Senate committee on Thursday the modelling on the rollout still hadn't been updated to reflect the 12-week interval.
Discussions are under way with Australian manufacturer CSL, where more than 50 million vaccine doses would be produced in Melbourne, to increase the speed of production. Prof Murphy said the main barrier to increasing production past 1 million doses a week was the "fill and finish" phase, when the vaccine was put into vials.
Australia's chief medical officer Paul Kelly told the Senate committee just three people had experienced anaphylactic allergic reactions after receiving the vaccine, and all were doing well. That was in line with predictions. He also said a small number of people had died in the days after receiving the vaccine, but those deaths weren't connected to the vaccine.
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