People who caught Covid in the first wave get ‘no immune boost’ from Omicron | Omicron variant

People who caught Covid during the first wave of the pandemic get no boost to their immune response if they then catch Omicron, a study of people who were triply vaccinated has found.

Experts say that while three doses of a Covid vaccine help protect individuals from serious consequences if they catch Omicron, previous infections can affect their immune response.

“If you got infected in the first wave, you can’t boost your immune response if you have an Omicron infection,” said co-author Professor Rosemary Boyton of Imperial College London. study.

The team also found that infection with Omicron offered little additional protection against capturing the variant. “When Omicron started flying around the country, people kept saying it was okay, it would improve people’s immunity,” Boyton said. “What we’re saying is that it’s not a good immunity booster.”

The team said the findings could help explain why reinfections with Omicron over a short period of time have been so common, adding that the findings were also important for vaccine development.

Writing in the journal Sciencethe researchers reported how they followed the vaccination and infection experiences of 731 triple-vaccinated healthcare workers in the UK from March 2020 to January 2022. The team then used blood samples taken from the participants in the weeks following their third dose of vaccine to explore their antibody and T-cell responses to the Omicron variant, BA.1.

Participants varied widely in terms of Covid history, including whether they had ever had a Covid infection and, if so, the variant involved.

The results suggested that, regardless of the participants’ infection history, a few weeks after their third Covid sting, their T-cell levels against Omicron proteins were low, while antibody levels against Omicron proteins were lower. to those against other variants.

But previous infections also mattered. Among other findings, the team reported that infection with Omicron increased protection against future infection by other variants. However, it only offered a limited boost in protection against another Omicron infection – a response that was actually weakened in those who had also had the original strain of the virus.

The team said the results held for antibody and T-cell responses, and suggested that those who caught Covid during the first wave of the pandemic did not improve their immune response if they later caught it. Omicron.

The researchers said the finding came as a surprise because it was generally assumed that a previous infection, even of a different variant, would act to boost an individual’s immune response.

Professor Danny Altmann, another study author, said that while Covid variants such as Omicron had previously been thought to have developed mutations in their spike protein that helped them evade immune responses, the situation was more complex.

“It’s actually worse than that, because the adaptations that the peak [protein] has now induced some kind of regulation or shutdown of the immune response,” he said, adding that if the study looked at responses to BA.1, similar results were likely for other subvariants. of Omicron.

The team added that with people in the UK having had very different histories of Covid infections and vaccinations, the study was important as it suggested that this ‘immune fingerprint’ would shape subsequent immunity against the virus. next variant.

Altmann said that while the low levels of hospitalization and death from Covid in the UK, despite high levels of infection, suggested that Covid bites continued to offer protection against death and serious illness, the results could be important for the development of new vaccines.

But he added that the results raised other concerns. “We don’t get herd immunity, we don’t develop protective immunity against Omicron,” he said. “So we’re faced with not coming out the other side of infections, reinfections, and breakthrough infections.”

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Edward L. Robinett