Nature Medicine: Sustained T cell responses to Omicron after infection and vaccination

Omicron has quickly become a major variant of the SARS-CoV-2 virus

However, severe disease appears to be relatively rare in vaccinated or infected people, suggesting that other components of the immune system are still able to recognize Omicron

"Together with viral factors, such as lower levels of viral replication in the lower respiratory tract, and other immune components, these results give us a clearer picture that may explain why previously vaccinated individuals with mRNA remain well protected from severe Omicron disease

The study, conducted in collaboration with Karolinska University Hospital in Sweden, is based on 40 vaccinated people, 48 people with mild or severe SARS-CoV-2 infection, and 48 previously Blood samples from people who were neither vaccinated nor infected

Memory T cells from both experimental groups showed good ability to recognize the omicron spike protein; however, the best response was observed in the vaccinated group

"These results suggest that boosting immunity may provide benefits that may extend beyond the induction of neutralizing antibodies to enhance protection against severe COVID-19 relapse,

Although the memory T-cell response to Omicron was overall intact, some individuals did not have the same response

"What we want to understand now is why everyone responds differently and whether a third dose of the vaccine could further enhance the T-cell response to omicron,

This research was supported by the sciilifelab/KAW National COVID-19 Research Project (funded by the Knut and Alice Wallenberg Foundation), the Swedish Research Council, Nordstjernan AB, the Swedish Cancer Society, the Swedish Childhood Cancer Foundation, the Öke Wiberg Fund Society, Swedish Medical Association, Stockholm and Karolinska Institute

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Progenitor SARS-CoV-2-specific T cells cross-recognize Omicron