Do I really have a window of immunity post-COVID? A doctor explains.

More than a million Australians have now contracted COVID-19, and if you're one of them, there might be a silver lining: a window of immunity post-infection.

Instead of avoiding large crowds and worrying about getting it for the first time (like me), you can theoretically hit the town knowing you probably won't contract the virus again.

But how long does immunity last for, and does it depend on which strain you contracted? Or is it all a myth?

We spoke to GP Dr Imaan Joshi to learn all about COVID-19 and immunity after infection. Here's what she shared.

But first, here are signs to use when talking about COVID. Post continues after video.

Are you immune to COVID after contracting it?

Unlike more stable viruses like chickenpox and measles, COVID-19 mutates rapidly - as we've seen with Delta and Omicron. Therefore, it is possible to get it again (like Carly did, here).

"Anytime you get an infection, in general terms, it boosts the immune system and its response against the virus for a period of time," Dr Joshi told Mamamia.

"In the case of some viruses such as chickenpox and measles, getting the infection confers a very high likelihood of lifelong immunity. For example, most people will have a one-and-done infection, and exposure even years later is unlikely to cause reinfection because of persistent immunity," she said.

"This is not the case with COVID and any of its variants, as far as we know."

OK. But are you immune to COVID for a period of time?

Yes! While you can get COVID-19 again, your immunity against the virus is most powerful following infection, making it very unlikely for you to get it soon after having it.

Here's how long you may have to work with:

"It’s believed at present you have up to six months of immunity post-infection, but this is a guess at best," Dr Joshi said.

"A study published out of Yale suggests that immunity is far more short-lived, around three months, following infection, which is why we encourage all eligible people to get vaccinated as soon as they’re recovered without delay even if their symptoms are mild.

"For this reason also, NSW Health has suggested that most people exposed to someone with COVID needn’t isolate if they’re within a month of COVID infection themselves as they’re unlikely to get reinfected that quickly."

While the study suggests you have months of immunity, Dr Joshi has noticed it's more likely shorter than that.

"It would appear most people are safe for at least a month after infection when the immune system is primed and boosted before immunity begins to wane," she said.

Does it depend on which strain you contract?

Short answer: no.

"There’s no evidence that any of the variants confer longer-lasting immunity," Dr Joshi said.

Listen to The Quicky, Mamamia's daily news podcast. In this episode, we discuss what is going on inside our hospitals, and whether there is any Plan B for when the system breaks down. Post continues after audio.

Does a booster protect you from not getting it again?

While vaccinations and booster shots protect you from getting extremely ill with COVID and overwhelming our hospitals, they unfortunately don't stop you from getting it again.

"At present, none of our vaccines confer sterilising immunity," Dr Joshi said. "I.e. none of them stop COVID from being transmissible to others, though it reduces it somewhat in vaccinated people."

But a third dose certainly helps.

"A third dose also significantly boosts waning immunity following two doses of any of the other vaccines - Astra Zeneca, Pfizer and Moderna."

And although temporary immunity post-infection is a good thing, it doesn't guarantee protection for yourself and others. So, continue to practice safety measures - keeping distance and wearing a mask - as new strains potentially come onto the scene.

Read more about COVID-19 here:

• So, you have COVID-19. Here’s exactly what you should do next.
• 'I tested positive to COVID at Christmas. Here's exactly how we avoided my partner getting it.'
• No longer positive, not quite recovered: What to know about the grey area after COVID-19.

Feature image: Getty.