Omicron provides no immunity to being reinfected

‘It is bad at inducing immunity, so we get reinfections ad nauseam and a depleted workforce’

CATCHING omicron does not protect against a future infection from the Covid variant, scientists at Imperial College have found.

They say their research could explain why Covid cases are remaining stubbornly high.

Throughout the pandemic, research has shown a previous infection provides immunity, often also protecting against other variants.

But the study has found there is virtually no extra immunity boost from omicron, leaving people at risk of being reinfected from the strain.

The study may help explain why cases are continuing to rise even though huge numbers of people have now had Covid.

The latest update from the government’s Coronavirus Dashboard dated June 9 shows Covid cases in England rose 64 per cent in the previous week, while hospitalisations increased by 33 per cent.

Prof Danny Altmann, from Imperial’s Department of Immunology and Inflammation, said: “The message is a little bleak. Omicron and its variants are great at breakthrough, but bad at inducing immunity, thus we get reinfections ad nauseam, and a badly depleted workforce.”

He added: “Not only can it break through vaccine defences, it looks to leave very few of the hallmarks we’d expect on the immune system.

“It’s more stealthy than previous variants and flies under the radar, so the immune system is unable to remember it.”

In the latest study, the team sought to find out why so many people have been reinfected with omicron, often quite soon after their initial bout. The team analysed blood samples from UK healthcare workers who had received three doses of MRNA vaccine, and who had different infection histories, to investigate antibody, T and B cell immunity.

They found that in people who were triple vaccinated and had had no prior infection, an omicron infection provided an immune boost against previous variants such as alpha, beta, gamma, delta and the original ancestral strain, but virtually nothing against omicron itself.

People infected during the first wave of the pandemic and then again with omicron also were found to lack any immunity boost, an effect that the researchers term “hybrid immune damping”.

Prof Rosemary Boyton, from Imperial’s Department of Infectious Disease and lead author, said: “Getting infected with omicron does not provide a potent boost to immunity against reinfection with Omicron in the future.

“A concern is that omicron could potentially mutate further into a more pathogenic strain or become better able to overcome vaccine protection.

“In this scenario, people who have had omicron would be poorly boosted against future infection depending on their immune imprinting.”

The research was published in the journal