Michelle Wakim, BTN Reporter: I'm pretty sure no one really wants to talk about COVID, ever again. We'd rather forget the lock downs, the case numbers, the vaccines, the masks, and the hand sanitising. But, while it's not a global emergency anymore...
Dr Tedros Adhanom Ghebreyesus, World Health Organisation: I declare COVID-19 over as a global health emergency.
COVID is still kicking.
Professor David Tscharke, Immunology and Infectious Diseases at the Australian National University: It's still out there. We can't kid ourselves. It is still killing people, and it's making other people very, very sick.
Professor Nicola Spurrier, SA Health: So we just need to understand as a community that we have got a COVID wave happening.
Peter Malinauskas, Premier of South Australia: When we see a spark in the number of COVID cases in an environment where most people aren't testing themselves anymore, you know there's a lot in the community.
We are now in our eighth COVID wave. This is being tracked by an increase in antiviral prescriptions, which are used to treat COVID, and hospital admissions. Oh, and there's some signs of it in our wastewater. This wave isn't like what we experienced during the pandemic, when Omicron and Delta spread quickly, and resulted in thousands of deaths.
Professor Tscharke: The current wave, we're not talking anything like that. So, we're talking about something that's, that’s been building up a little bit more gradually. To a large degree, this is because so many people were vaccinated.
In early October, the latest vaccine booster was approved and is set to be rolled out in Australia from the 11th of December. So, is this something we still need to be thinking about? And why, after all this time, would we still need boosters?
Professor Tscharke: Okay so probably where I will start with, with actually, how does your body fight an infection, right?
This is Professor David Tscharke. A specialist in immunology and infectious diseases. He says, to understand vaccines, first we need to understand the body.
Professor Tscharke: The analogy that I, I kind of use is that if your body is like a country, a virus is like an invader in your country. It's a really sneaky and terrible kind of invader, because it only needs to send a few troops in to start with, and those troops can make copies of themselves and try and take over your body. Your immune system does a couple of things. The very first thing it does, is it realises something bad is happening. And it starts throwing a variety of weapons at the virus, at the invader.
These first weapons are broadly anti-viral and not tightly targeted, so they have some pretty uncomfortable side-effects on the whole body, like aches, pains, fever and fatigue. Then comes the part two of the immune response.
Professor Tscharke: And what that does is starts to recognise exactly what virus it is and it makes very special weapons that target just that one virus.
To do this, special cells are recruited to help fight an infection. These are B-Cells, which make antibodies to stop the invaders spreading, and T-cells, which can kill off the invader. Both of these cell types also record information about the infection and how best to fight it, in case the invader tries again later. But while the immune system is doing this, the virus is working as hard as it can to get ahead.
Professor Tscharke: So essentially what you have is a race between the virus trying to make more copies, which is going to make you feel bad, and the immune system gearing up, making more troops and making more weapons.
So, what happens if we could change the dynamics of this race?
Professor Tscharke: What you need to understand about vaccines is that all you're trying to do with a vaccine is exactly the same thing that would happen when your body fights an infection, but you're doing it without the virus that can make you sick.
So, a vaccine teaches our body how to respond if it is ever threatened. It gives the body the parts of the virus that the immune system needs to see to create a specialised defence against that particular virus, before you’re even infected.
Professor Tscharke: The race starts with your immune system already ahead of the game.
But, vaccines lose their effectiveness over time, for a couple of reasons. If your body doesn't see a virus for a while, it kind of forgets it was ever a threat. COVID is also pretty sneaky and can evolve or mutate into new strains.
Professor Tscharke: Because this infection is going around and because a lot of people have immunity right, and this immunity has got a very particular shape, the virus is going to start changing its shape, to try and still be able to infect in people who have got some immunity.
So, to keep up with the race long term, our bodies need a little bit of help. A boost, even. Boosters are a slightly lower dose of vaccines. The ones available at the moment are different from the original COVID vaccines, as they've been developed to keep up with new COVID strains that are circulating throughout the community.
Professor Tscharke: You know, it’s kind of like virus control on your computer, you constantly got to get upgrades right, because the virus has changed.
Right now, the recommendation is for vulnerable demographics to stay up to date with boosters. That includes those older than 65, or anyone with complex health needs because their bodies may not be as efficient in producing the cells that fight infections. And anyone 5 years of age or older is eligible for a booster if it's been 6-months or longer since their last COVID shot or confirmed infection. On top of this, authorities say it's not a bad idea to remember other things we can do to help stop the spread, like wearing a mask in busy or high-risk places, sanitising and washing our hands, and staying home if we have symptoms or test positive.
Professor Tscharke: You know, it is useful to think about when something like COVID is around, and there are people who are vulnerable, and that might not be you, but be considerate of other people.