“Yes … and no,” says the Doherty Institute’s Dr Jennifer Juno, who has been studying the immune response to COVID-19. “Unfortunately, we’re well into an area where the nuances become everything.”

The hope is that with nearly all eligible Australians now vaccinated, infection with Omicron will act like a natural immunity booster against this and future variants, without making you seriously ill.

This cycle – infection, waning immunity, infection, waning immunity – could continue endlessly as COVID-19 becomes endemic. – (The endless cycle of the ‘Jabberthon’ – Mick Raven)

A study published by the US Centres for Disease Control on Wednesday found vaccination offered better protection than prior infection until Delta arrived – and then it was prior infection that offered better protection (the best protection was provided by a combination of prior infection and vaccination). Another study from South Africa finds Omicron infection seems to offer some protection against Omicron and Delta.

“I think it makes sense that infection with a current variant provides good protection against that particular variant, and boosts immunity against other variants to a lesser but still significant extent,” says the head of infection epidemiology at the Kirby Institute, Dr Deborah Cromer.

Unfortunately, other evidence suggests things aren’t so neat. Juno has been leading a study looking at the effect of reinfection on immunity. The results are not clear-cut. Some people get a great boost to their immune levels; others don’t.

That brings us back to the great unknown: the next variant. It is plausible that a new variant could arise that happily evades the immunity generated by natural infection. There is some evidence that people who were infected with Beta have very poor immunity to Delta, for example.

Is Omicron the final variant? If there are more, will they be even milder?

The rise of Omicron has many people pointing to a popular notion of viral evolution: over time, viruses evolve to become more contagious and less deadly. Viruses, the saying goes, don’t really want to kill their hosts because otherwise they’d have no one left to infect. This calming narrative suggests that eventually COVID-19 will become so mild it will be little more than a cold.

A virus’ virulence – how lethal it is – will evolve up or down depending on how it affects how contagious the virus is. If a mutation makes the virus both more lethal and more contagious, it’s got a good chance of sticking.

Alpha was more lethal than the variant of COVID-19 that first emerged from Wuhan; Delta was more lethal than Alpha.

The narrative of a weakening virus has a second problem: Omicron did not evolve from Delta.

That knowledge means we cannot be confident the next variant will be an evolution of Omicron – or even of Delta. It could come from anywhere, with attributes we cannot predict.

The best bet in this pandemic remains the same: expect the unexpected.

Lets hope I am wrong about the next Covid19 variant ‘Omega’ – Mick Raven