I’m under 40 – should I get the AstraZeneca vaccine?

This article was originally posted on the 30th June and updated on the 13th July.

Prime Minister Scott Morrison has announced that anyone under the age of 40 can now request the AstraZeneca vaccine from a GP.

The announcement followed new COVID-19 cases in New South Wales, Queensland, Western Australia and the Northern Territory, which led to lockdowns, border closures and tightened restrictions.

It was also made just a week and a half after the Australian Technical Advisory Group on Immunisation (ATAGI) increased the recommended age for AstraZeneca vaccines to 60 and above, leading to confusion and even distrust of the medical consensus.

“Undoubtedly, I think 50 to 60 year olds will feel uncomfortable and annoyed that they ‘feel’ they have been put at increased risk,” says Jill Carr, a virologist at Flinders University.

“It will undoubtedly increase scepticism that the government and scientists know what they are doing. But in reality, this is real science, and recommendations change as more information becomes available, situations change and the risk/benefit for vaccination changes. Of note, I think the recommendation for AstraZeneca in the UK was over 45 – a different risk/benefit scenario and hence different recommendation.”

Why did the advice change?

Medical and scientific advice does, and will continue to, change as new evidence and risk factors are considered. This may make it seem like those giving the advice are flip-flopping, and causing confusion among consumers as to which advice to follow, especially with the abundance of media coverage concerning AstraZeneca and blood clots.

Important to note: ‘flip-flopping’ isn’t really correct in this case.

“The original advice provided by ATAGI on the use of the AstraZeneca COVID-19 vaccine on the 17th June has not changed,” says Roger Lord, a senior lecturer in medical sciences at the Australian Catholic University and researcher at the Prince Charles Hospital, in Brisbane.

This statement was made on the 29th of July, prior to the updated ATAGI recommendations on the 13th of July. The AGATI has revised advice concerning people in outbreak zones, but advice for others remains the same. The following information is still in line with current recommendations.

“ATAGI still recommends Pfizer as the preferred vaccine for people under the age of 60, but the restrictions around who can get a vaccine have changed,” says Lord.

People under 40 are now able to request an AstraZeneca vaccine from a GP, regardless of existing age or vulnerability guidelines. That means that personal choice (and vaccine availability) issues have now been put into play – without any government restriction, although medical advice from a GP must still be sought and considered.

Expert reaction to this change has been mixed.

“I suspect the federal government is reacting to the possible increased transmission of the Delta variant of COVID-19 and significant shortages of the recommended Pfizer vaccine for individuals under the age of 60 years,” says Lord.

“The government is therefore now trying to encourage increased vaccination against COVID-19 by indicating individuals under the age of 60 can request the AstraZeneca vaccine despite previous medical advice from ATAGI that this presents a greater risk to those under 60 years.”

Significantly, the Prime Minister’s advice “to go and have that discussion with your GP” was not endorsed by the president of the Australian Medical Association, Omar Khorshid.

“It took us by surprise, and it’s hard to know how to take that announcement because I think it’s going to be a limited number of people to take it up, given that they would be going against the expert ATAGI recommendation,” says Korshid.

“My guess is that they are wanting to provide nervous Australians who are going into lockdown this week with something that they can actually do to improve their chances of getting through this and to push the nation’s vaccination program forward.”

This statement was released on 30th June. The AGATI has since clarified new recommendations in light of increased infections in the Greater Sydney Area.

Presently, the Delta variant has been shown to be more infectious, and appears to have been spread during very brief encounters, meaning it could potentially be a lot harder to control.

It has also been identified in multiple states, compounding the risk of it spreading to vulnerable communities and leading to multi-state lockdowns.

Read more: Vaccine efficacy on variants

The risk of blood clots from AstraZeneca’s COVID vaccine is a concern to many people, which may be why the new eligibility criteria requires a doctor’s visit.

“I would say this: it’s normal to feel concerned about the risk of [blood clots] – it’s serious, even though it’s rare,” says Julie Leask, an expert in immunisation communication at the University of Sydney. “When people have any vaccine, they should look at the advice on early signs of reactions to report for prompt diagnosis and treatment.

“The big picture is also important. [A blood clot] is a risk at a single point in time, whereas the benefits of vaccination and the immunity it provides extend into the future, to ourselves, our families and communities.”

What about the risk of getting a blood clot?

The steady media coverage about blood clots related to AstraZeneca has made this particular vaccine, in some quarters, seem like the ‘bad vaccine’. Unfortunately, the context of these cases hasn’t necessarily been clear.

In Australia to date, two people have died of AstraZeneca-related thrombosis (blood clot) out of a total of 4.2 million vaccine administrations.

In its report released on 24 June, the Therapeutic Goods Administration noted that “the total Australian reports assessed as [blood clots] following the AstraZeneca vaccine [were] 39 confirmed cases and 25 probable cases, with a total of 64 cases overall from approximately 4.2 million doses of the AstraZeneca vaccine.

“When assessed against the criteria used by the US Centers for Disease Control and Prevention, fewer than half of them are classified as Tier 1 cases, which involve clots in an unusual location, such as the brain or abdomen.”

Read more: AstraZeneca and blood clots: by the numbers

The blood-clot cases occurred predominantly in people aged between 50 and 79, but the reports may show a bias since the majority of the people being vaccinated were in that demographic. Statistics from the UK still suggest people below 50 are at a slightly increased risk (19 cases per million).

With the chance of catching the more infectious Delta strain significantly increasing in the past two weeks, the risk of severe illness due to COVID-19 far outweighs the risk of vaccine side effects. 

The total number of suspected cases of thrombosis following the administration of AstraZeneca in Australia is currently at 15 per million, but the total confirmed cases of locally acquired COVID-19 cases in Greater Sydney in the last four weeks is 132 per million.


“The [currently] reported Australian cases of thrombosis and thrombocytopenia syndrome (TTS) following administration of the AstraZeneca vaccine for COVID-19 must be kept in perspective,” says Lord.

“The association between the vaccine and the risk of developing an adverse event afterwards continues to have been made without consideration and examination of an individuals’ own personal level of risk.

“The continual reminders and reinforcement of these events only fuels fear of vaccination and hesitancy, which is against the public interest.

“Reported cases of these adverse events following administration of the AstraZeneca vaccine have automatically been assumed to be a result of the vaccine rather than a case-by-case evaluation of risk factors that may have increased the likeliness of [blood clots] occurring in an individual.”

Administration of the vaccine poses a threat only twice, and while the occurrence of blood clots is 14.2 cases per million after the first vaccination, it decreases to 1.5 per million after the second dose.

This needs to be compared to the constant threat of contracting COVID-19 every time there is an outbreak.

Why only AstraZeneca?

It all comes down to supply.

“We do have surplus doses that are currently not being used so there is some capacity to bump up the delivery,” say Khorshid.

Currently, the only two approved vaccines available in Australia are Pfizer and AstraZeneca. Pfizer cannot be manufactured onshore and needs to be imported, whereas AstraZeneca is being made in Australia.

This means Pfizer availability is limited, but AstraZeneca supplies are available to potentially increase the speed of the roll-out.

Read more: AstraZeneca COVID vaccines now sit on the shelf. What next?

“Until we get enough supply, some may not be able to access Pfizer when they want to, particularly in the younger age groups,” says Leask.

“This will intensify during outbreaks when we see a surge in vaccine demand. For the most part, we hope that most jurisdictions can manage the extra demand until we see a ramp-up in supply later in the year.

“As we face these issues in Australia with low supply, it’s worth remembering countries in the region with large outbreaks of COVID where there is not enough of any vaccine and a slow trickle expected. I think keeping perspective is important for us as we consider our role as global citizens and good neighbours.”

I’m still worried. Should I wait for Pfizer?

The short answer is that there’s no short answer – it really depends on risk and advice.

The most effective way to prevent COVID-related illnesses, deaths and lockdowns is through mass vaccination. This means the long-term benefits of getting a vaccine at the earliest possible time, regardless of the one to which you have access, almost certainly outweigh the benefits of waiting.

But does that mean you should ignore expert advice?

“Our recommendation is still really for patients to follow the ATAGI advice. Be patient and have the ATAGI-recommended vaccine when it’s available. I am certainly still backing the expert advice at this stage,” says Khorshid.

Update – As of the 12th of July, the AGATI issued the following update.

“In the context of a COVID-19 outbreak where the supply of Comirnaty (Pfizer) is constrained, adults younger than 60 years old who do not have immediate access to Comirnaty (Pfizer) should re-assess the benefits to them and their contacts from being vaccinated with COVID-19 Vaccine AstraZeneca, versus the rare risk of a serious side effect.”

It refers exclusively to people in areas of high COVID-19 cases who cannot immediately access a Pfizer vaccine. The advice has been updated because of risk assessments that consider the current outbreak numbers. A discussion with a GP is still required.

Risk assessment based on low risk of COVID-19 infection

A chart showing different risk of adverse reaction compared to hospitalisation over age groups
Low Exposure – Infection rate similar to first wave of COVID-19 in Australia (29 infections per 100,000 people in a 16-week period). *TTS =Thrombosis with thrombocytopenia syndrome (blood clots). It includes all probable and confirmed cases. Credit: AGATI.

Risk assessment based on medium risk of COVID-19 infection

Capture 2
Medium Exposure – Infection rate similar to second wave of COVID-19 in Victoria (275 infections per 100,000 people in a 16-week period). *TTS =Thrombosis with thrombocytopenia syndrome (blood clots). It includes all probable and confirmed cases. Credit: AGATI.

So, if you are within the recommended demographics for AstraZeneca – yes.

“I strongly encourage everyone to get their vaccine shots ASAP, which is the best way to stop COVID,” says Johnson Mak, a virologist at Griffith University. “Both the AstraZeneca and Pfizer version of COVID vaccines are highly effective.”

“Recent data shows even a vaccine that had lower efficacy in clinical trials [than AstraZeneca and Pfizer vaccines] can dramatically control the pandemic virus. A Brazilian town experiment shows mass vaccination can wipe out COVID-19, but it will only work if we (as a collective/nation/citizens) take them.”

Read more: Cosmos Q&A: vaccines, antivirals and why you should get a jab

Early vaccination may also combat the propensity for SARS-CoV-2 to mutate into concerning strains – such as Delta – that current vaccines may eventually no longer be effective against.

“Whilst Delta is listed as a variant of concern, the data from vaccinated populations in the UK are promising,” says Stuart Turville, an immunovirologist at the University of New South Wales’ Kirby Institute. “Vaccination is our key defence and until we have higher rates, we need to treat this variant and all variants like we have done in 2020.”

Carr agrees. “I do not believe that at present there is a threat to vaccine efficacy due to the variants of concern. Maybe minor effects, but breadth of responses should still give protective immunity in my opinion.”

Bottom line: the extra AstraZeneca shots could go a long way towards reaching vaccination goals.

“We do have surplus doses that are currently not being used so there is some capacity to bump up the delivery,” says Khorshid.

“Of course, if Delta really does ingrain itself in our community and the lockdowns aren’t successful or they’re too slow, then speeding up the vaccination program by using more options on the table is wise.

“The problem, of course, unfortunately, is that for the Delta virus you need both doses to get reasonable protection against Delta and for AstraZeneca, that’s a minimum of eight weeks apart.”

Update – Due to the COVID-19 situation in New South Wales, the AGATI has revised advice to state that the timeframe for receiving the second dose of AstraZeneca be between 4 and 8 weeks. This is exclusive to people in an outbreak area. All others are still recommended to receive a second dose at 12 weeks.

This article is based on scientific evidence but is not medical advice. Please speak with your doctor for advice regarding your personal circumstances and vaccines for COVID-19.

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