Dr Lucas De Toca: antibody tests, testing positive for COVID-19 and COVIDSafe travel

Good morning, my name is Doctor Lucas De Toca and I lead the Department of Health's primary care response to COVID-19. Welcome to Top Three. As usual I am joined today by James who will be doing Auslan interpreting, and in fact, my shout out today goes to the deaf community and to people who use Auslan. Happy Auslan day.

As usual we are on Ngunnawal country so I want to pay my respects to those people. I would also like to extend that acknowledgement to the traditional owners of the lands where people may be watching from. I also want to thank James for his patience when he teaches me a little bit of Auslan, and I butcher it.

Today we have a number of questions about the COVID-19 vaccinations, as a primary reminder before we kick off, I just want to reassure you that all the most up-to-date information continues to be available on Health.gov.au, on Health Direct, or on the National Coronavirus Helpline, 1800 020 080.

If you have any doubt go to those resources for up-to-date verified information.

First question, can I get an antibody test once I have received the COVID-19 vaccination?

Yes, so, I think it is important to differentiate antibody tests from PCRs or polymerase chain reaction tests, which is the test that you get to find out whether you have an active infection from COVID. Antibody tests, as the name says, measure antibodies. Antibodies are very small particles, very small proteins that your body, your B type white blood cells produce to fight infection. They are little molecules that attach to viruses, bacteria, to any particle that should not be in your body, close it, and either neutralise it so that it cannot cause infection, or signals to the other elements of the immune system that this thing is here, it needs to be neutralised, and needs to be destroyed. So they are a really important part, they are only one component, but a really important part of how our body fights infection through the immune response.

Antibodies are produced as a response to infection, normally with a lag between being exposed to the infection, mounting up a response, and being able to produce them in a quantity high enough to then make sure that any virus or bacteria is identified, coated, and neutralised. Antibodies are also produced as a response to vaccines, in fact that is how vaccines work. They show your body something that allows your body to recognise the infection, so that if you encounter the real thing later on, you already have the antibodies to fight it. Antibodies are produced, as I said, a couple of weeks, depending on the time, a few days to a couple of weeks after exposure to the infection or vaccine, but once you have them and if there has been sufficient exposure they can last for quite a long time and respond really quickly when you are further exposed to that pathogen, to that invader.

That is why for some vaccines, including the COVID vaccines, you need two doses. The first one allows you to recognise, your body to recognise the viral particle, for our vaccines there is no live virus for this dose, no bits of the virus, it helps your body make the bits of the virus that are recognised by your immune system. The second dose, it make sure that your immune system is maintained and you can generate memory cells, that are a type of white blood cell that allows for the continued production of antibodies even months after the exposure. Antibody tests are not routinely used to diagnose COVID, the PCR tests, the genetic tests are what is used to check for the virus. So, routinely people do not have an antibody test audit, and you don't have a requirement to have an antibody test after you get the vaccine. Antibody tests at the moment are using very specific contact tracing and outbreak investigation follow-up by public health units and officials in the states and territories, when they are trying to work out whether there is a missing link in a chain of transmission, and whether someone may not have the virus currently but has had a past infection. As most people become vaccinated it may become a little bit difficult to differentiate past infection from vaccinated people, but the important thing is once you have the vaccine you can be comfortable and confident that you are achieving protection against the virus and you don't need to follow up with an antibody test.

Second question, will I test positive for COVID-19 once I have received the vaccine?

No. This is one of those questions that I can give a long explanation, but the actual answer is pretty straightforward. The standard test for COVID-19 that I mentioned before, the chain reaction test or PCR test, what they do if they detect whether there is any of the genetic material of the virus circulating in your body. They amplify the molecule to detect whether there is any actual virus in your body, or sometimes they can pick up remnants of the virus even if you don't have living viruses, and you are just clearing an infection, but there is still bits that can trigger the test. COVID-19 vaccines, either the AstraZeneca or Pfizer, do not contain a virus, so they will not trigger that polymerase chain reaction test. When you get the vaccine, the AstraZeneca one, it helps your body recognise parts of that virus but it does not contain itself. So, once you get the vaccine you will not test positive for COVID-19 PCR test. And in fact, it is important that even after you have had the vaccine, even if you have cold and flu systems, if you are concerned you may have COVID-19 you still get a test and isolate at home until you get the result, because we still don't know whether these vaccines completely protect against having an infection, we know they are exceedingly good, almost 100% at preventing hospitalisation, severe disease and death, but we're still learning and getting more evidence on whether they prevent infection altogether. You will not test positive but you can still get COVID-19, although you are very protected from severe consequences from COVID-19.If you have had your vaccine and you have cold and flu symptoms later, the advice remains, get a test, and isolate until you get a result.

Finally, what are some of the COVIDSafe things I need to remember if I plan to travel this year?

So, this year we have been in a really enviable situation compared to the rest of the world in which the majority of days in 2021 thus far, we have not had any community transmission from COVID-19. We have had a few events of community transmission following importation from international border that had led to some very swift responses by public health officials to contain those clusters and prevented them from growing into an outbreak, as we have seen in Brisbane and other places, but overall we are in a really positive situation with little to no COVID in our community. That means that domestic travel is happening and it is actually encouraged so we can support our regions as we continue into our COVID-19 normalcy society. We are soon going to be talking about travel to New Zealand as part of the trans-Tasman travel bubble that was announced. It is a really exciting moment in which we can still see for those who have relatives within Australia and/or New Zealand, we still look forward to singing our loved ones while we still wait to see our loved ones overseas, while the international borders remain closed. However, as we have seen with the clusters in Brisbane and other places recently, the threat from COVID remains, and the risk of importation and community transmission remains. As always the COVIDSafe measures we have all been implementing over the past 14 months so will remain our first line of defence to make sure that we minimise the risk of having COVID, but also that if we have COVID in community we can detect it swiftly and limit the transmission. So, the usual recommendations we have been droning on about for the last 14 months and you know very well, still remain.

Make sure that before you travel, while you are planning it but also on the day of your travel, you check your destinations health Department website to see if there is any specific restrictions, advice on wearing masks, or regulations on permits or what you need to do prior to accessing the jurisdiction, he is up-to-date with those public health regulations and obey them at all times. Make sure you practice physical distancing, and in crowds, and try to avoid large gatherings if possible. Wash your hands often, especially using soap and water, that is the most effective, but if not you can use hand rub and sanitise as long as it is at least 60% alcohol. Check into venues, most states and territories have designated apps for that, others have other mechanisms, but practically everywhere you have those QR codes available and if you don't have a phone or the capacity to sign in that way you can sign with pen and paper. Make sure you do it because it is a really important tool to facilitate contact tracing. And as he said before, if you feel unwell, even with mild symptoms, even now, please get a test and stay-at-home, isolating until you get the results, which these days is very quick. It is important we continue to do these things as the vaccine rollout continues to ramp up, we will have to continue to do these COVIDSafe behaviours for quite some time as we progress in our vaccination, but together as we have done it over the last 14 months we can continue to beat this virus and live our lives as normal as possible, as we are doing right now.

Thank you so much for watching. Thank you so much for staying COVIDSafe, thank you James, happy Auslan Day, and see you next time.