We now have the best evidence yet that everyone develops long-term coronavirus immunity after infection — and it’s not just about antibodies

Scientists may now have an answer to one of the most crucial lingering questions about COVID-19: whether people develop long-term immunity.

Early research suggested that coronavirus antibodies — blood proteins that protect the body from subsequent infections — could fade within months. But in their concern about those findings’ implications, many people failed to consider our immune system’s multilayered defense against invading pathogens.

Specifically, they discounted the role of white blood cells, which have impressive powers of recollection that can help your body mount another attack against the coronavirus should it ever return. Memory T cells are an especially key type, since they identify and destroy infected cells and inform B cells about how to craft new virus-targeting antibodies.

A study published Friday in the journal Cell suggests that everyone who gets COVID-19 — even people with mild or asymptomatic cases — develops T cells that can hunt down the coronavirus if they get exposed again later.

“Memory T cells will likely prove critical for long-term immune protection against COVID-19,” the study authors wrote, adding that they “may prevent recurrent episodes of severe COVID-19.”

That’s because memory T cells can stick around for years, while antibody levels drop following an infection.

Even patients without antibodies have virus-specific T cells

The authors of the new study examined blood from 206 people in Sweden who had COVID-19 with varying degrees of severity. They found that regardless of whether a person had recovered from a mild or severe case, they still developed a robust T-cell response. Even coronavirus patients who did not test positive for antibodies developed memory T cells, the results showed.

Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, called T-cell studies like this one “good news.”

“There’s a lot of hot stuff going on right now” in T-cell research, Fauci said during a NIAID Facebook Live interview on Thursday, adding, “People who don’t seem to have high titers of antibodies, but who are infected or have been infected, have good T-cell responses.”

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