Covid Booster Shots: Why do I Need a Third Vaccine? - VITAL+ Pharmacy

Now that Australia has reached beyond the 80% double vaccination mark, Covid booster shots are now available to book with a registered medical practitioner. But there’s a little confusion as to who is eligible, what vaccine should you get and when, and if in fact you actually need a third vaccine? Here are all your Covid booster questions answered.

Last week, it was announced that Australia had officially reached the 80 per cent double vaccination mark — more than 17 million Australians or 82.8 per cent of the population aged 16 or over are now fully vaccinated against COVID-19.

From December we should start to see current restrictions lifted for all vaccinated and unvaccinated Australians.

But of course that doesn’t mean that we can’t still contract COVID-19. The risk is now even higher as the more infectious and deadly Delta variant tears across the world — a recent Canadian study found that a person infected with Delta is one and a half times more likely to die that someone with the Alpha variant, was twice as likely to be hospitalised regardless of their age, and the chances of them ending up in intensive care were also higher than people infected with any other variants.

So, in a bid to protect even further from the virus, people in Australia aged 18 and over who have received two doses at least six months ago, are now eligible for a third vaccination — known as a booster shot — to improve their protection against COVID-19.

What is a Covid booster shot and how does it work?

Much like the first and second vaccine doses, the booster vaccine technology works in the same way — they stimulate an immune response that produces protective antibodies so your body is equipped to fight off the infection.

Essentially, the vaccine teaches your immune system to fight the actual virus if it encounters it.


Are two Covid vaccines not enough?

The first two doses of the COVID-19 vaccine provide good enough protection, but because the effect of the antibodies wears off over time, your immunity, or protection against Covid, will also lessen over time, putting you more at risk of contracting the illness, and the severity of your symptoms.

The booster shot has therefore been designed to offer stronger and longer-lasting protection against the virus, to either stop you getting sick or substantially reduce the severity of your symptoms, and the reduce the chance of transmitting the virus to others.


How effective are the boosters?

The AstraZeneca, Pfizer and Moderna vaccines have all been proven effective at minimising a person’s risk of getting COVID-19 if they encounter the coronavirus.

If you’ve had both doses of the vaccine, you're more likely to be protected from COVID-19 than someone who isn’t. The booster vaccine lessens your risk even more by producing a stronger immune response — it prolongs that strengthened immunity so your body’s natural defence system (the immune system) is able to fight off the illness for a longer period of time.

There will unfortunately still be some infections, but having that extra booster will protect you from severe disease, hospitalisation and death, as a result of contracting COVID-19 — in fact, recent trials found that Pfizer’s booster shot was 95.6% effective at preventing symptomatic Covid-19 compared to those who did not receive an additional shot.

Basically, if you do contract the illness, having a booster shot means you are less likely to develop a severe reaction.

Which Covid booster shots are available in Australia?

At this stage, the Therapeutic Goods Administration (TGA) has approved the Pfizer vaccine for the booster shot, even if you had another vaccine for your primary doses.

Health Minister Greg Hunt has confirmed that he expects other vaccines, including Moderna, to be added, pending approvals from the Therapeutic Goods Administration.

Although not preferred, AstraZeneca boosters will be administered only to those:
who had the AstraZeneca vaccine for their first two doses without an adverse reaction, and those who can’t have an mRNA vaccine (Pfizer or Moderna) for medical reasons or who had a significant adverse reaction to a previous mRNA vaccine.

Is Pfizer more effective than Moderna?

The Pfizer and Moderna vaccines are both made using messenger RNA, or mRNA, a technology that delivers a bit of genetic code to cells — this is essentially a recipe to make the surface protein (known as spike) on the SARS-2 virus.

The proteins made with the mRNA instructions activate the immune system, teaching it to see the spike protein as foreign. The immune system then develops antibodies and other immunity weapons it needs to fight off the illness.

In short, they’re actually both incredibly similar in terms of their chemical make-up and their efficacy — large phase 3 clinical trials showed the Moderna vaccine was 94% effective at preventing severe disease, and Pfizer was 95% effective.

The key difference between the two is that is that Moderna can be kept at minus 20 degrees rather than minus 70 like the Pfizer vaccine. Moderna is much easier to store, making it easier for more GPs and pharmacies to administer.

It’s likely Australians in eligible groups will be offered either Moderna or Pfizer boosters and given their similarities, it really doesn’t matter which one you have – they’re both very effective.

You can book an appointment for the Moderna vaccine if you are 12 years old or over.

You need 2 doses of the Moderna vaccine, given at least 4 weeks apart.
You can book an appointment for the AstraZeneca if you are:

  • 60 years old and over
  • 18 to 59 years old – you can choose to have AstraZeneca after discussing with your health professional.AstraZeneca doses can be given 4 – 12 weeks apart, but the Australian Technical Advisory Group in Immunisation recommend doses should be 12 weeks apart.

You can book an appointment for the Pfizer vaccine if you are 12 years old or over. Pfizer doses are given at least 21 days apart.

How often will I need a booster?

Earlier in October, Pfizer boosters for people who are severely immunocompromised were made available in Australia. For the more vulnerable and at risk groups, the booster shot is currently available 28 days after the second dose, irrespective of what vaccine you had to start with.

For everyone else, it’s recommended to book in for a booster vaccine six or more months after your second dose, to ensure that the protection from the first doses is even stronger and longer-lasting.

A fourth dose is not recommended at this stage.

Who is eligible for the booster?

From 8 November 2021, Australians aged 18 and over who have received two doses at least six months ago, are now eligible to have a booster shot.

Do I have to have a booster?

The booster shot is not mandatory, however it provides further protection against the worst effects of COVID-19.

Are there any risks or side effects?

As the booster shots are the same vaccines used for the earlier shots, the advice on side effects is expected to track along the same lines. Health authorities around the world are closely observing any long-term effects, but currently some of the documented side effects include muscle aches and pains, headaches, nausea and fever.

You can read more about how to treat your Covid vaccine side effects here.

You can book your AstraZeneca or Moderna vaccine with us now. Book online and we’ll organise a convenient time for you to pop into our Kings Cross store.

Loved our advice on Covid booster shots? We've got plenty more health advice to check out on our Health & Wellness Edit.
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