Australia is now pinning its hopes on the Pfizer coronavirus vaccine as authorities across the country fathom how new health advice affects the jab rollout.
The AstraZeneca vaccine is no longer recommended for people under 50 because of an extremely rare but serious blood clot side effect.
That age group has been told to opt for the Pfizer option, with the government hoping an extra 20 million doses arrive in the country by the end of the year.
It would take Australia's total supply of Pfizer jabs to 40 million.
Prime Minister Scott Morrison originally pinned October as the rollout deadline, but now won't say when all Australians can expect to have their first jab.
"We're not in a position at the moment to reconfirm a timetable," he told reporters in Canberra on Friday.
But Mr Morrison stressed that the side effect was rare, saying the AstraZeneca option was still recommended for people over 50.
He stressed that there was no ban on AstraZeneca vaccines for people under the age of 50.
But the health advice has plunged the rollout around the country into chaos, with most people originally expected to receive the AstraZeneca jab.
Western Australia cancelled appointments for people under the age of 50 who had been expecting to get the AstraZeneca vaccine on Friday.
They will be contacted by officials to discuss the latest advice, while people who were due for their second dose were told to still get it if they had no side effects after the first.
The jab rollout has been paused in Queensland's far north as authorities work through the implications of the rare blood clot advice.
Vaccinations in the Torres Strait have been a priority for Queensland given its number of vulnerable communities and proximity to the outbreak in Papua New Guinea.
Plans have also been derailed in the Northern Territory, because the Pfizer vaccine needs to be stored at much cooler temperatures than AstraZeneca.
This makes it harder to transport to remote areas outside of Darwin and Alice Springs that do not have specialist medical refrigerators.
NSW is still working on its plans to create mass vaccination hubs to vaccinate tens of thousands of people each week, but it is reliant on supply.
State premier Gladys Berejiklian said supply had been "lumpy" so far and that NSW would need notice so the hubs could alter operations depending on which vaccine would be used.
Labor is again urging the federal government to lock in deals for other vaccines, particularly the Moderna jab.
Labor senator Katy Gallagher said the government had a lot of work to do to ensure the Australian community had confidence in the vaccine rollout.
More than one million Australians have now been vaccinated, with the government also promising more frequent data on how the rollout is progressing.
Australian Associated Press