Omicron might evade antibodies

With the highly mutated omicron variant spreading rapidly, people want to know if immunity from vaccination or a prior infection will be enough to protect them against getting infected or developing severe disease.

If prior immunity does provide sufficient protection, then precautionary measures to slow omicron’s spread, together with vaccinating and boosting people, should prevent intolerable strain on healthcare systems. But if not, then increased social restrictions are inevitable as the variant spreads around the world and potentially replaces delta, which is currently the dominant variant.

Early studies – all of which are still preprints, so yet to be formally reviewed by other scientists – suggest that omicron is handled less well by existing immunity. But research also suggests that giving a third booster vaccine dose may provide protection. So, the bad news isn’t as bad as it could be, but the good news also needs to be treated with caution. Here’s why.

More to immunity than antibodies

Inevitably, early reports have focused on the most quickly accessible data, which is the amount of antibodies people have in their blood that are capable of neutralising the new variant.

Overall, the data consistently suggest that omicron can escape these neutralising antibodies to some extent: the reduction in neutralisation in double-vaccinated people is somewhere between 10- to 20-fold to 40-fold compared to delta. That said, in people who had received two vaccinations and had also been infected, the level of neutralisation of omicron was higher.

This may seem alarming. But it’s not the whole story. In previous studies that have looked at earlier forms of the virus, levels of neutralising antibodies have correlated well with levels of protection – greater neutralising activity equating to better protection.