Living with Covid has taken on a whole new meaning in 2022.
We had been prepared for the virus remaining in our communities, but Omicron has taken this to a different level. This is what “vaccine-escape” looks like.
As we watched the Delta outbreaks in New South Wales and Victoria slowly come under control in 2021 with the rise in the number of people completing our primary course of vaccination, we had every reason to be optimistic for some relief over summer, even with international and state borders opening.
But this was dashed with the arrival of Omicron before the year was even over.
Omicron took off in South Africa, where first reported, then progressively made its way around the world, peaking in Australia on 14 January this year. It was worryingly capable of establishing vast waves quickly wherever it landed, and not just because it was intrinsically more adept at spreading. It is most successful because of its ability to evade our immunity.
Neither prior infection nor vaccination provides much protection from infection with this variant. This is immune escapism, which comes from being physically different enough from other variants that our immune system doesn’t immediately recognise them to mount an attack, and Omicron represents a bigger step change than we saw in the previous immune escape creep with Delta – so much so some are arguing Omicron should not be lumped together with the other Sars-CoV-2 variants seen in this pandemic at all.
Immune escape undermines the immune system’s ability to ward off an infection, but thankfully we still have enough cross immunity from vaccination, infection, or both, to reduce our risk of serious illness. In the peak last January, we had more than 50 times the infections reported in the Delta wave, but only one-third more people in ICU.
What is even more quirky about this Omicron variant, and all its subvariant spinoffs, is that an Omicron infection does boost our immunity against coronavirus infection, just not against Omicron. You are less likely to get Delta after an Omicron infection, but reinfection with Omicron is still on the cards, especially with the succession of new subvariants that have followed BA.1.