Almost a third of the country is now eligible for a COVID-19 vaccine – but the availability will depend on where you live.

Eight million Australians are now eligible to receive the AstraZeneca vaccine as the federal government ramps up the rollout of national immunisation against COVID-19.

Australians aged over 50 have been brought forward in the government’s vaccine timeline as part of phase 2a.

From today, over-50s can get the jab at Commonwealth-run respiratory clinics and state and territory-run vaccination centres, which are the first to offer AstraZeneca vaccines under phase 2a.

From May 17, over-50s will be able to receive the AstraZeneca vaccine at participating general practitioners.

Phase 2a includes adults over 50, Aboriginal and Torres Strait Islander adults aged between 18-49 and “other critical and high-risk workers”.

Australia’s chief medical officer, Dr Brendan Murphy, said concerns over rare blood clotting from the AstraZeneca jab for under 50s had freed up a large number of doses for over 50s.

That led to the national cabinet’s April 22 decision to move forward phase 2a.

“Clearly we have to encourage Australians to get vaccinated; we have to make sure that we have a program that is credible,” Murphy said last month.

“The AstraZeneca vaccine is the vaccine for people 50 years and over. Because the states and territories will be no longer providing AstraZeneca to under 50s in their clinics, that will free up more AstraZeneca to go to primary care sites.”

While approximately eight million Australians over 50 are eligible, receiving the AstraZeneca jab may depend on what state you live in.

Victorians can book an appointment at one of the state-run centres or walk into one but that will require a wait. They can also phone 1800 675 398 to make an appointment.

However, New South Wales health officials have said they would focus on priority groups state-run centres from May 3.

NSW’s capacity will rise significantly once its mass vaccination centre opens at Sydney Olympic Park in mid-May.

Only those at risk will be offered an appointment and the vaccine would not be available to all residents aged over 50 in the state-run centres.

To find out if and when you can receive a vaccine, use the federal government’s eligibility tracker.

Also beginning today, state-run facilities whose refrigeration capacity qualifies to store the Pfizer will be able to offer that vaccine to Australians aged under 50 who are eligible in phases 1a and 1b.

The changes fr leaves the remainder of phases 2a, 2b and 3 waiting to receive the Pfizer.

Phase 2b includes the rest of the population aged between 16-49.