Top 3 COVID-19 vaccine questions – Vaccines and child immunisation schedules, RAT false positives and Novavax

Doctor Sonya Bennett, Deputy Chief Medical Officer, answers the Top 3 questions across our channels.


Hello, everyone. My name is Dr Sonya Bennett. I am the deputy chief medical officer in the Department of Health. This morning, I’m going to address some of your questions, the top three questions that we’re seeing on our social media channels. But first, I’d like to start by giving a shout-out to all the public health practitioners out there who have been working tirelessly, really since the beginning of the pandemic. So, if you’ve ever had COVID or been a contact of somebody who had COVID, you may well have received a call from a public health practitioner, commonly known as contact tracers, but the public health workforce is much broader than contact tracers. It includes public health doctors, public health nurses, epidemiologists, laboratory staff, infection control practitioners who all work together to really identify cases and manage the cases and their contacts to prevent ongoing further transmission in the community and the impact of COVID on the community. And I’m sure you can agree it can be a difficult task at times, and they do it with commitment and dedication, so shout-out to public health practitioners.

But now to our first question that we are going to address today, and question number one is, Will the COVID-19 vaccine be added to the childhood immunisation schedule? So COVID-19 will be with us for many years into the future, but it’s not really known yet how often and how regularly that we will need further vaccinations. So, it does make sense from a public health perspective to consider a COVID vaccine on the national immunisation program, if we, as a population, require further vaccines into the future. But in practice, adding a vaccine to the national immunisation program is a major undertaking with funding, purchasing and delivery models all needing to be worked out. So as we transition from an emergency situation to business-as-usual in the coming months to years, we are likely to see these arrangements evolve, and more information will become available about whether vaccines are included on the NIP or not. And in parallel, new developments in vaccine technology may see different vaccines, and, in fact, different schedules and timings being introduced, so all that information is really important for us to understand how we might manage vaccines into the future. In the meantime, though, very important to note that everybody aged five years and over remains eligible for a free COVID-19 vaccination, and also those aged 16 and over, eligible for a booster, so Australians can expect to continue to receive COVID vaccine boosters under existing arrangements, and they are free, and they are available and accessible in many, many places so with the vaccines approved by the TGA at the moment.

So our next question is a little more complex. The question is, How common are false positive rapid antigen test results? So, rapid antigen test work by detecting the presence of specific proteins of SARS-CoV-2, which is the virus that causes COVID, and any rapid antigen test approved in Australia by the TGA must have an accuracy rate, which we call a sensitivity, of at least 80%. So that means that at least 80% of tests, we can expect to be accurate in detecting infection in somebody who has infection. What that does mean though is that up to 20% of test results, depending on what test you are using, might be a false negative. So it is very important that if you do continue to have symptoms and you have a false negative rapid antigen test that you either re-test or you seek out a test through a PCR test which is our gold standard. Now, a false positive occurs when infection is detected by the rapid antigen test but the person being tested actually doesn’t have COVID. They may be sick. They may have another illness, but it’s not COVID. Now, this is much more stringent. So the TGA sets what we call a specificity rate at 98%. This means that only 2% of tests might incur a false positive. So you can be fairly confident that if you have a positive test result from a rapid antigen test, you should manage it as you’re being advised to with COVID and stay home and isolate for 7 days, seek medical attention if you become very unwell. So that is reassuring that if you get a positive, you can be fairly confident that it is a positive.

The third and final question that we are answering today is, Can I get a Novavax vaccine if I’ve had a different brand for my first two doses? So we know the TGA provisionally approved Novavax for use in Australia on 20 January, just recently, 2022, for use in people aged 18 years and over. So you need two doses of Novavax vaccine, given at least three weeks apart, to be considered fully immunised with what we call your primary course. Now, we know there is interest in the potential for Novavax being used as a booster. And we do expect that people who receive Novavax for a primary course will need a booster at some stage. But those details are still being worked through, and the approval for Novavax to be used as a booster is not yet in place. So, anyone who has Novavax as a primary vaccine course, if you are eligible for a booster, which is still some time down the track, three months, you can check then whether Novavax is approved as a booster. And if not, we already have Pfizer and Moderna approved for use as a booster in those circumstances.

So thank you for your time and listening today. I hope that has been useful in answering some of the questions, and we’ll see you at the next session.

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