Government favours Pfizer over AstraZeneca for under 50s

Due to "very rare" and potentially deadly side effects experienced by a tiny portion of younger recipients of the AstraZeneca COVID-19 vaccine, the Federal Government has now recommended a preference for the Pfizer vaccine in people aged under 50. 

The recommendations, presented to the Federal Government this evening by the Australian Technical Advisory Group on Immunisation (ATAGI), mean the later stages of the national vaccine rollout will have to be adjusted.

It also sees the Federal Government place the onus on the public to decide whether or not they will receive the AstraZeneca vaccine, with health officials developing resources to let Australians give "informed consent" before recieving the jab.

Health officials still encourage older Australians receive the "highly effective" AstraZeneca vaccine, as side-effects are less likely for people aged 50 and over. 

Health Minister Greg Hunt emphasised this blood clot condition is extremely rare around the world. 

"This remains a highly effective vaccine, safe for over 50s on the advice we've received," Hunt said.

Chief Health Officer Paul Kelly outlined five recommendations to the public regarding the AstraZeneca vaccine:

1. At the current time, the use of the Pfizer vaccine is preferred over the AstraZeneca vaccine in adults aged less than 50 years who have not already received a first dose of the AstraZeneca vaccine.
2. Immunisation providers should only give a first dose of AstraZeneca COVID-19 vaccine to adults under 50 years of age where the benefit clearly outweighs the risk in individual circumstances.
3. People that have had their first dose of the AstraZeneca vaccine, without any serious adverse events, can safely be given their second dose. This includes adults under the age of 50.
4. People who have had blood clots associated with low platelet levels after the first dose of the AstraZeneca vaccine should not be given the second dose.
5. The Department of Health further develop and refine resources for informed consent that clearly convey the benefits and the risks of the AstraZeneca vaccine for both immunisation providers and consumers of all ages.

Prime Minister Scott Morrison has stressed the choice to receive the AstraZeneca vaccine is still up to the individual.

"This is not a directive. This is not an instruction," the PM said.

"Why we're here tonight is just to be very upfront with Australians, so Australians can know that they're getting all the information that we have, and they can feel informed about the decisions they make about their own health.

"We want to empower them in those decisions."

Until today, most young Australians were set to receive the AstraZeneca vaccine later in 2021 as part of the Federal Government's staged vaccine rollout.

In light of the Government's decision to adopt ATAGI's recommendations, the rollout will be recalibrated. This process will be conducted over this coming weekend.

Department of Health Secretary Professor Brendan Murphy says authorities are talking to Pfizer to secure more supply of its vaccine. Additional supply would build on 20 million doses of the Pfizer vaccine already secured. 

"Pfizer have committed to 20 million doses this year, and we're working with them almost on a daily basis to see when they can increase their supply," says Murphy.

"We're confident that at some stage in the near future we will get improved supply of Pfizer. 

"We will finish [vaccinating] aged care in the coming weeks, and that will free up the Pfizer vaccine, and all of that Pfizer will go to those under 50."

Taking guidance from European data

ATAGI has held two meetings over the past two days as the AstraZeneca vaccine side-effects issue has escalated worldwide, with the European Medicines Agency (EMA) yesterday declaring a "possible link" to very rare cases of unusual blood clots with low blood platelets.

In a similar vein as Australia's "informed consent" response, the EMA reminded healthcare professionals and people receiving the vaccine to remain aware of the possibility of these rare side effects within two weeks of vaccination.

"So far, most of the cases reported have occurred in women under 60 years of age within 2 weeks of vaccination. Based on the currently available evidence, specific risk factors have not been confirmed," the EMA said.

"People who have received the vaccine should seek medical assistance immediately if they develop symptoms of this combination of blood clots and low blood platelets," the agency reported.

These conditions include shortness of breath, chest pain, swelling in your leg, neurological symptoms such as severe and persistent headaches or blurred vision, and tiny blood spots under the skin beyond the point of injection.

The EU's Pharmacovigilance Risk Assessment Committee (PRAC) carried out an in-depth review of 62 cases of cerebral venous sinus thrombosis and 24 cases of splanchnic vein thrombosis reported in its drug safety database (EudraVigilance) as of 22 March, 18 of which were fatal.

"The PRAC noted that the blood clots occurred in veins in the brain (cerebral venous sinus thrombosis, CVST) and the abdomen (splanchnic vein thrombosis) and in arteries, together with low levels of blood platelets and sometimes bleeding," the agency said.

"COVID-19 is associated with a risk of hospitalisation and death. The reported combination of blood clots and low blood platelets is very rare, and the overall benefits of the vaccine in preventing COVID-19 outweigh the risks of side effects.

"One plausible explanation for the combination of blood clots and low blood platelets is an immune response, leading to a condition similar to one seen sometimes in patients treated with heparin (heparin induced thrombocytopenia, HIT)."

In response, the committee has requested new studies and amendments to ongoing ones to provide more information and will take any further actions necessary.

Updated at 7.39pm AEDT.