Everything you need to know about COVID vaccines

From who will get it first, to side effects and when jabs will be available — here’s what you need know about Australia’s vaccine rollout.

No vaccines have yet been approved for use in Australia. Picture: Getty Images

Pfizer/BioNTech: Made in America, Belgium and Germany by Pfizer/BioNTech. Succeeded in phase three human clinical trials. Expected to receive TGA approval in Australia by the end of January. Rollout to start in late February, with 10 million doses to be delivered from overseas and the option to purchase more.

Pfizer/BioNTech: Made in America, Belgium and Germany by Pfizer/BioNTech. Succeeded in phase three human clinical trials. Expected to receive TGA approval in Australia by the end of January. Rollout to start in late February, with 10 million doses to be delivered from overseas and the option to purchase more.

AstraZeneca Vaccine: Developed by University of Oxford and British-Swedish pharmaceutical company AstraZeneca. Succeeded in phase three human clinical trials. Now being manufactured in Melbourne by CSL and expected to be approved by TGA early this year. Australia has purchased 53.8 million doses, 50 million of which will be produced here.

Novavax: Made in Europe, developed by American company Novavax. Still in phase three human clinical trials, with results expected in the first half of this year. Australia has purchased 51 million doses.

How many doses of the vaccine will we need?

It is expected that the Pfizer, AstraZeneca and Novavax vaccines will all require two doses. Medical experts don’t know yet how long that immunity will last.

Can we mix and match vaccines?

Not initially. The plan is for people to receive two doses of the same vaccine. Professor Peter Doherty says more research is needed to determine if mixing and matching could be a possibility. But people could receive a different vaccine in the future if it is determined to be more effective or longer-lasting.

How will these vaccines protect us?

Phase three trials for the Pfizer and AstraZeneca vaccines show they are successful at preventing COVID-19 symptoms. The efficacy rate – the number of people who contracted COVID-19 but did not have symptoms – was 90 per cent for Pfizer and 70 per cent for AstraZeneca in those trials. Both completely prevented severe illness. “[With a vaccine] you limit the extent of infection and damage that can occur,” Prof Doherty said. “You don’t necessarily stop the virus, but if you stop it near the bottom end you will be fine. If you let it go … you can get enormous damage.”

What’s the difference between the vaccines?

Pfizer is developing an mRNA-based vaccine, meaning it does not contain any “live” virus.

It instead carries code or message to the body’s cells, directing them to synthetically grow a replica of the virus’s spike protein, which is responsible for initiating infection. This sparks an immune response and the production of antibodies.

AstraZeneca is developing a viral vector vaccine made from an adenovirus which causes the common cold in chimpanzees. It has been modified to mimic COVID-19. When injected, cells in the body express a replica of the virus’s spike protein. This stimulates the body’s response and production of antibodies.

Novavax is developing a protein-based vaccine which uses the “genetic sequence” of the virus to create a lab-made spike protein. When injected into the body, this kickstarts the body’s immune response and generates antibodies.

Are some better than others?

It’s still too soon to say. When the federal government purchased vaccine candidates, there was no evidence any would succeed. Pfizer and AstraZeneca are now proven to prevent serious illness, but further research is needed on the effectiveness of preventing transmission and creating herd immunity. “Early on we didn’t know what we were going to get with vaccines,” Prof Doherty says. “We’ve got the best information on Pfizer and it’s looking better, but I’d like to know more about the AstraZeneca and Novavax vaccines – Novavax looked really good at the start … But it’s all a matter of time. I don’t think any product will go to waste, they will still be useful.”

What is herd immunity and how can it be achieved?

If enough people are vaccinated against a virus, it is hard for it to spread. This is called herd immunity. This also protects people who are vulnerable or can’t be vaccinated, such as newborn babies and some cancer patients. There is currently little data on which COVID-19 vaccines will be most successful at creating herd immunity. Prof Doherty said it was estimated at least 70 per cent of the population would need to be vaccinated or have developed immunity to the virus (from catching COVID-19) for herd immunity to be achieved, especially given the new highly infectious strands in the UK and other parts of the world.

Can Australians pick which vaccine you get?

Not at this stage. The Pfizer vaccine will be available first and given to the highest priority groups, including aged care residents and staff, frontline healthcare workers, and border and quarantine officials. The AstraZeneca vaccine should then be approved and will be distributed more widely. Prof Doherty suspects which vaccine Australians get will depend on when they are being vaccinated and what is available at that time. “There is a limited amount of vaccine to go around the planet so we can’t expect the manufacturers to give us any priority,” he said.

Are the vaccines safe for everybody? Are there any groups that have had adverse reactions?

Prof Doherty says “any medical intervention has some element of risk” but there is limited evidence to suggest any major adverse reactions. Cancer patients and other vulnerable people battling illnesses may not be able to be vaccinated but broader evidence is still needed.

Pfizer has reported cases of people who have had allergic reactions to the vaccine outside of clinical trials, which they are monitoring. They did not test the vaccine on people with a reported severe history to any of their ingredients.

There are claims that the vaccines could be dangerous for pregnant women. What is the science around this?

There is currently no evidence to suggest the vaccine may be dangerous for pregnant women, however most clinical trials thus far have not included women who are expecting.

Pfizer is expected to start trials on pregnant women in early 2021.

Are they safe for older people?

The AstraZeneca trial assessed 1418 people over the age of 55. A report published in the medical journal The Lancet recently stated: “from the interim analysis of these trials, we cannot yet infer efficacy in older adults, who are the group at greatest risk of severe COVID-19 outcomes.”

The Pfizer vaccine has been reported as about 94 per cent effective in those aged over 65.

About 41 per cent of their 43,000 trial participants were aged 56 to 85.

What are the key rollout dates in Australia?

The rollout timeline is still to be determined, but the Pfizer vaccine is expected to be the first to receive TGA approval by the end of January, with jabs to be given from late February. The AstraZeneca vaccine is expected to be approved within weeks as well. Health Minister Greg Hunt said the government aimed to complete the vaccination program by October.

How will it be rolled out?

The Pfizer vaccine must be stored at -70C, so it will be distributed through up to 50 hospital hubs. The AstraZeneca vaccine can be more easily rolled out through GPs and pharmacists.

How will I be notified?

A public information campaign will begin soon which will explain when and how Australians can be vaccinated.