Could the COVID-19 Virus Evade the Vaccines?
The Omicron variant's ability to evade vaccine protections against infection has raised concerns about what the ever-mutating coronavirus may have in store next. According to the latest research, we will need to shift our attention from antibodies to another, even more important part of the immune system.
BOSTON – It is now well known that SARS-CoV-2 can mutate to evade vaccine protection against infection. The Omicron variants – BA.1, B1.1, and BA.2 – can infect those who were previously infected by other variants, even when vaccinated. And though a third booster shot offers some protection from an Omicron infection, it wanes after three or four months, leaving most people susceptible to reinfection. That said, the immunity conveyed by prior infection or vaccination still dramatically reduces the incidence of hospitalization and death.
We also have come to realize that our main saviors against COVID-19 turn out not to be antibodies, but rather another part of the immune system: our T cells. Studies show that the strength of our long-lived T-cell response to SARS-CoV-2 proteins – especially by T cells that recognize the virus spike protein – strongly correlates with the degree of protection.
There are two types of T cells, CD4+ and CD8+, which are distinguished by proteins on their surface. Because CD4+ T cells mostly assist in the production of antibodies, the CD8+ T cells are the real heroes of the story. Once they identify an invader they remember from a previous encounter, they act quickly to move in for the kill, demolishing infected cells and cutting short the life cycle of the virus.
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