Contracting omicron does not protect you from future infection

Studies conducted throughout the pandemic have shown that a previous infection provides immunity against catching COVID-19 again, as well as often protecting against other variants.

But new research has found that there is virtually no extra immunity boost from getting omicron, leavingpeople 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 been infected with Covid.

The latest update from the Government’s coronavirus dashboard from June 9 shows that Covid cases in England rose 64% in the previous week, while hospitalisations increased by 33%.

Professor 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 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 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.

Professor 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.

Omicron BA.5: No one is fully protected

Due to the global increase in coronavirus cases caused by the BA.5 subvariant, the World Health Organization (WHO) currently classifies it as a "variant of concern." Experts at Germany's top health agency have warned that infections will likely increase this summer, Deutsche Welle reported.

Germany's Robert Koch Institute (RKI), the country's national public health organization, reported on June 9 that the omicron subvariants BA.4 and BA.5 are growing faster than all other variants and concluded the two could soon be responsible for the majority of the country's cases.

The BA.5 variant already accounts for 10% of current infections — twice as many as last week.

Like other omicron subvariants, BA.5 infections are milder than infections with other COVID strains, like delta.

The protection provided by COVID vaccines or past infection slowly decreases over time as antibody levels drop.

That means no one is fully protected from BA.5 — new infections are possible despite vaccination and/or past infection and occur more frequently than with past variants.

But there have been fewer deaths and hospital admissions.

According to experts, this is because many millions of people are vaccinated or have antibodies, making the general immunity of the population higher than at the start of the pandemic.

Nevertheless, the RKI recommends that the elderly and people in risk groups get another their booster vaccine for extra protection.

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