An infection with the Omicron variant of COVID does little to spice up our immunity in opposition to subsequent an infection, even amongst individuals who have been triple jabbed, in line with new evaluation.
The discovering might clarify why so many individuals have been contaminated a second time in the course of the Omicron wave, even with Omicron itself.
“Getting contaminated with Omicron doesn’t present a potent enhance to immunity in opposition to re-infection with Omicron sooner or later,” says Professor Rosemary Boyton, an infectious illness immunologist at Imperial’s School in London who led the research of COVID in UK healthcare staff..
The outcomes recommend an infection with Omicron is not going to essentially supply elevated safety in opposition to the BA.4 and BA.4 sub-variants of COVID now on the rise within the UK.
Nonetheless, the analysis solely appeared on the danger of an infection with COVID – vaccination continues to offer good safety in opposition to extreme illness and demise.
The research drew on blood samples from greater than 700 healthcare staff in London who’ve been adopted since March 2020. All had acquired three doses of a COVID vaccine however had totally different histories of an infection.
It allowed the researchers to research the “boosting” impact of various COVID infections, and likewise have a look at the function performed by totally different elements of the immune system: antibodies, B-cells and T-cells.
The image that’s rising is that safety in opposition to an infection with subsequent variants of COVID varies relying on an individual’s an infection and vaccination historical past – a course of described as “immune imprinting”.
They discovered those that by no means had COVID, however grew to become contaminated with Omicron after three doses of vaccine had good B and T cell immunity in lab assessments in opposition to earlier variants like Alpha, and Delta – however much less safety in opposition to Omicron.
However earlier an infection with different variants did not have a lot affect on immunity to Omicron both.
These contaminated with Alpha earlier within the pandemic had much less of an antibody response in opposition to Omicron. And their Omicron an infection did not then enhance their total immune response.
Co-investigator Professor Danny Altmann, additionally at Imperial, stated: “We’ve discovered that Omicron is way from a benign pure booster of vaccine immunity, as we’d have thought, however it’s an particularly stealthy immune evader”.
Omicron “flies below the radar, so the immune system is unable to recollect it”, he added.
This discovering flies within the face of the concept of “herd immunity” build up within the inhabitants over subsequent waves of the pandemic.
Regardless of that, the sample across the globe – up to now at the very least – is that subsequent waves of COVID variants are inflicting fewer hospitalisation, much less extreme illness and demise.
This implies that regardless of folks’s an infection or vaccine historical past, total there’s a rising immunity in opposition to extreme COVID.
However Omicron’s powers of immune evasion, and the very fact new sub-variants are evolving, does not assure that that pattern will maintain true, the Imperial School crew argue.
“A priority is that Omicron might doubtlessly mutate additional right into a extra pathogenic pressure, or develop into higher in a position to overcome vaccine safety,” says Prof Boyton.
“On this situation, individuals who have had Omicron an infection can be poorly boosted in opposition to future an infection relying on their immune imprinting.”