Three week gap between Pfizer jabs pushed to six weeks

The three-week gap between Pfizer jabs has been extended to six weeks in some states as the nation struggles with shortages.

Exclusive: The gap between Pfizer jabs has almost doubled for three of the nation’s biggest states, as they try to counter a drastic shortage of Covid-19 vaccines.

New South Wales is now following Victoria’s lead in adopting a six week gap between appointments for patients at state vaccination clinics, while Queensland said the second dose did not need to be given at exactly three weeks.

It can be revealed, however, some Pfizer patients in New South Wales are being given appointments seven weeks apart, in the latest hitch in the program.

And it comes as others are having to wait until November to get a first AstraZeneca shot through their GP even though we have an oversupply of that vaccine.

Former Australian Medical Association president Dr Mukesh Haikerwal said the delays were down to logistics because the states “can’t get the vaccine, they are waiting for the second dose to arrive”.

A gap of up to six weeks between Pfizer jabs is allowed by the nation’s expert advisory body on vaccines the Australian Technical Advisory Group on Immunisation (ATAGI).

In its advice to the government in February ATAGI said “the recommended interval between two doses of Comirnaty (Pfizer) is at least 21 days”.

To allow for logistical considerations such as vaccine supply “it is recommended to complete the two-dose course within six weeks”, the advisory body said.

University of Newcastle Immunology expert Associate Professor Nathan Bartlett said “three weeks is really a minimum amount of time” you could have between doses and dosing earlier than that might compromise the body’s immune response.

“The main role of that first immunisation is to establish sort of a baseline level of immune memory from which you can then develop a more robust secondary response, via the second or the booster immunisation,” he said.

“Three weeks is really the amount of time it takes to reliably know that you’ve established that immune memory.”

No research had been conducted into the maximum time you can leave between doses but Assoc. Prof. Bartlett said studies of AstraZeneca vaccines had shown a longer, 12 week gap, worked better.

Research shows the Pfizer jab was between 33 to 50 per cent effective after the first dose and 88 to 95 per cent effective after the second dose, given three weeks apart.

The downside of a longer wait was people were not fully protected until they had their second dose particularly against the Delta variant — which is dominant among cases in Australia.

Three week delay between Pfizer doses pushed out to sic weeks in big states (Photo by Lisa Maree Williams/Getty Images)

Last month Simon, who asked for his surname to be omitted, spent three days trying to get an appointment for a Pfizer shot, finally securing an appointment at Sydney’s mass vaccination site at Homebush on July 15.

However, he was shocked to discover he had to wait until September 1 for his second inoculation.

“I feel exposed,” the self-employed 58 year old said.

”I won’t be fully protected for ten weeks and Covid is circulating all around Sydney.”

Simon eventually managed to get an earlier appointment for his second jab on August 5 in a Canterbury clinic using HotDoc.

Simon’s mate Patrick, 51, had an even worse experience trying to book an appointment for an AstraZeneca shot. His GP told him they were booked out until November.

The NSW health online booking system told him it would get back to him in 24 hours but he endured a nine day wait and was then told he had an appointment in three months and 20 days’ time.

He tried the ACT health system and HotDoc but was caught in a spiral because both systems would only offer him the Pfizer shot.

Delaying second Pfizer dose not a problem says expert. (Photo by Lisa Maree Williams/Getty Images)

Last month some Victorians were being given a six week gap between Pfizer appointments a move its chief health officer Professor Brett Sutton said “is fine”.

A Queensland Health spokesperson said the state was “currently prioritising anyone in Phase 1a and 1b and those who are due to receive their second Pfizer dose”.

“The second dose does not need to be given at exactly 21 days after the first dose. There is a window in which you can receive your second dose. The second dose should be aligned as close to this window as possible,” the spokesperson said.

A spokesperson for SA Health said it was continuing to deliver Pfizer jabs at three week intervals.

The only time that would not happen is if a person failed to book a second appointment at the same time as their first and then they would get the next available appointment three weeks after their first shot.

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