How jab can raise your chance of infection
Doctors warn it's vital that you make time to get the second dose of the two-shot COVID-19 vaccine with the evidence suggesting you're most at risk of infection between the first and subsequent dose.
That's why getting vaccinated against COVID-19 in Australia will require not one but two jabs and you will probably need a booster shot down the track.
In most cases you will be asked to come back to receive your second dose in around three weeks.
Vaccinating against COVID-19 is the easiest way for Australians to get their normal lives back, but millions are hesitant to get the jab.
Our Best Shot is news.com.au's campaign answering your questions about the COVID-19 vaccine roll out.
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"All COVID-19 vaccines require two doses per person,'' deputy chief medical officer Michael Kidd told news.com.au.
"The Pfizer vaccine doses will be administered 21 days apart."
The exact spacing between the doses depends on the vaccine and may differ depending on the brand being used whether that's Pfizer, AstraZeneca or any new vaccines that are approved by Australia's TGA.
WHY DO I NEED TWO SHOTS OF THE VACCINE?
There is a one-shot COVID vaccine in development by Johnson & Johnson but there are no plans to import it yet.
Both the Pfizer-BioNTech and the AstraZeneca vaccines, the first to be offered in Australia, require two doses to offer the full benefit.
The first dose helps the immune system create a response against SARS-CoV-2, the virus that causes COVID-19.
It offers good protection against COVID-19 with an efficacy rate of more than 50 per cent in most vaccines.
But the official advice for Australia's Therapeutic Goods Administration makes it clear that the protection is not instantaneous.
"As with any vaccine, vaccination (it) may not protect all vaccine recipients. Individuals may not be fully protected until seven days after their second dose of COMIRNATY,'' it states.
The protection is stronger after the second dose of the vaccine.
Research shows that the vaccines are more than 50 per cent effective 10 days or so after the first shot and nearly 95 per cent effective several days after the second.
It's the second dose that further boosts the immune response to ensure long-term protection with protection rising to up to 95 per cent in the case of the Pfizer vaccine.
HOW LONG WITH THE COVID-19 VACCINE LAST?
That's a big question that scientists haven't fully answered yet.
Because the vaccine is so new, scientists have not been able to run real-time trials determining how long it will last and when you need a booster shot. If you take the example of the flu vaccine, the effectiveness can vary.
How long the vaccine will reduce the severity of disease is currently being researched through global clinical trials.
In other words, scientists are still researching whether a booster shot will be required annually, like the flu shot, or less frequently.
"We don't know how long these vaccines are effective for because they're so new. So whether we need to do a booster at some point remains to be seen,'' chief medical officer Pauk Kelly said.
The vaccine itself lasts for six months and must be kept in cold storage in freezing temperatures.
That's one of the reasons why the Pfizer vaccine, which is regarded as perhaps the most effective vaccine on the market, also has disadvantages from a logistical point of view.
The multidose vial must be stored frozen and thawed prior use.
Frozen vials should be transferred to an environment of 2C to 8C to thaw or alternatively thawed for 30 minutes at temperatures up to 30C for immediate use.
Reporting any serious side effects and adverse reactions is important.
Originally published as How jab can raise your chance of infection