From this week, the number of GP clinics delivering the Pfizer vaccine will swell to around 500.

There are hopes it’ll help set the nation up to more efficiently distribute the bulk shipments of Pfizer when they land around October.

Why haven’t GPs been distributing Pfizer before now?

When the Pfizer mRNA vaccine was first developed, its makers believed it needed to be kept at sub-zero temperatures of between -90 degrees Celsius and -60C.

This made the logistics of transporting and storing the vaccine challenging, and so only state-run vaccination sites were distributing Pfizer to begin with.

But since then, we’ve learnt more about how the vaccine can be safely stored.

ABC News: Danielle Bonica

“Once it’s been thawed from super-cold temperatures to vaccine fridge temperatures, we know that the vaccine remains stable for 31 days,” the Royal Australian College of General Practitioners’ Anita Munoz said.

“So that means that general practices can get involved because they can use the fridges that they’ve always had at their disposal.”

Once that issue was resolved, GP clinics began to join the Pfizer rollout, with some of the first ones in Victoria beginning the rollout in May and early June.

How will this change the rollout?

While state-run vaccination hubs have been able to vaccinate large numbers of people at a single site, the bulk of the nation’s vaccinations to date have been delivered through GP clinics.

“General practice undoubtedly is the most efficient way to vaccinate a population, because we’ve been doing mass vaccination for decades in the form of the flu vaccine and we also vaccinate children of course, and we’re responsible for the majority of travel vaccines,” Dr Munoz said.

“So the logistics are there and general practitioners and practice nurses are very well trained in vaccine delivery. What this means is that the Pfizer vaccine will now be dispersed throughout the whole of the country, in people’s communities, where general practice is.”

On Sunday, Australia’s Deputy Chief Medical Officer Michael Kidd said around 40 per cent of the 500 GP clinics beginning to deliver Pfizer were in rural areas.

ABC News: Eliza Laschon

“During this month, another 800 general practices will come online with the Pfizer vaccine as well as the AstraZeneca vaccine. This includes many Aboriginal community controlled health organisations, which will be offering the Pfizer vaccine progressively through July and August,” Professor Kidd said.

Dr Munoz said the availability of Pfizer could give greater comfort to Australians who would prefer to get the vaccine somewhere close to home and after consulting a doctor with whom they had a trusted relationship.

How is our supply?

This continues to be the biggest constraint on vaccinating Australians under 60 years of age.

The Australian Technical Advisory Group on Immunisation (ATAGI) recommends Pfizer as the preferred vaccine for those under 60, due to the very small risk of clotting with the AstraZeneca vaccine.

But Pfizer cannot be manufactured locally, meaning Australia is reliant on supplies bought and shipped in from overseas.

The federal government has said it expects to receive around 2.8 million Pfizer doses this month, up on 1.7 million doses in June.

But the bulk of Pfizer doses are due to arrive from October, with 40 million doses of Pfizer (and Moderna) vaccine due for the final quarter of the year.

“Absolutely the fourth quarter of this year will be a time of huge activity, and I think it is a very welcome move that as many general practices as possible are ready and already vaccinating and have their programs solidly in place for that time,” Dr Munoz said.