In addition, other parts of the immune system can remember and destroy the virus for many months, even years, according to at least four studies published in top medical journals in the last month.
The research revealed that specialized immune cells called T cells, produced after immunization with four brands of COVID-19 vaccines — Pfizer-BioNTech, Moderna, Johnson & Johnson and Novavax — are about 80 percent equally potent against the omicron than against other variants. Given how different omicron mutations are from earlier variants, it’s highly likely that T cells will mount an equally strong attack on any future variants, the researchers said.
This aligns with what scientists have discovered about the SARS coronavirus, which killed about 800 people in Asia during an epidemic detected in 2003. In people exposed to that virus, T cells have lasted over 17 years. So far, the evidence indicates that the new coronavirus’s immune cells — sometimes called memory cells — might also decline very slowly, experts said.
“Memory cell responses can last for years,” said Wendy Burgers, an immunologist at the University of Cape Town, who led one of the studies published in the journal Nature. “Potentially, the T-cell response is quite long-lasting.”
Throughout the pandemic, a disproportionate amount of research has focused on antibodies, the body’s first line of defense against a virus. In part, that’s because these molecules are relatively easy to study. They can be measured from a drop of blood.
Immune cell analysis, by contrast, requires milliliters of blood, skill, specialized equipment, and a lot of time. “It’s much slower and more labor intensive,” Burgers said.
Few laboratories have the means to study these cells, and their findings lag weeks behind those of the antibodies. That could explain why scientists often overlook the importance of other parts of the immune system, experts say.
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