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Why You Might Be Partially Immune to Coronavirus Right Now

Your immune system might have this curious response.
girl wear medical face mask on sunny city street

Scientists are theorizing that many people may be "partially immune" to coronavirus even without having been infected with the disease, the Washington Post reported Friday.

The starting point for the theory is a statistic that has frustrated public-health officials from the beginning of the pandemic: Up to 40% of people who are infected with coronavirus may be asymptomatic. The fact that so many people can be out in public spreading the disease while seeming healthy made it frustratingly difficult to track and contain.

But some researchers think that might have a potential upside: That there are so many people who get coronavirus and don't get sick—and so many for whom the illness is a mild one—could mean their immune systems somehow know how to mount a response to the virus and weaken it, if not prevent infection.

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"A high rate of asymptomatic infection is a good thing," Monica Gandhi, an infectious-disease specialist at the University of California at San Francisco, told the Post. "It's a good thing for the individual and a good thing for society."

"Memory" cells may attack and defend

There is no immunity to SARS-CoV-2 per se; the novel coronavirus is indeed a new virus. But in some people, the immune response could be carried out by "memory" T-cells—the part of the immune system trained to attack invading pathogens—spurred into action by bits and pieces of their previous training. Childhood vaccines, for example. Or encounters with other coronaviruses like the common cold, a new paper published in the journal Science suggests.

"This might potentially explain why some people seem to fend off the virus and may be less susceptible to becoming severely ill," said National Institutes of Health Director Francis Collins this week.

The concept of "herd immunity" relies on the number of people who test positive for antibodies to a particular pathogen. Antibody tests for coronavirus are available. But T-cells—also known as the body's "helper" and "fighter" cells—are not part of that test.

But don't stop washing your hands

Dr. Anthony Fauci, the nation's top infectious-disease expert and a key member of the White House pandemic response team, told the Post that those ideas are being investigated but the theories are premature. "He agreed that at least some partial preexisting immunity in some individuals seems a possibility," the paper said.

Fauci emphasized there are many reasons why people do or don't contract a virus, or experience a mild or serious case. Those include age, genetics and pre-existing health conditions.

So he reiterated his constant advice on how to protect yourself from coronavirus: Scientific data backs frequent handwashing, wearing face masks, limiting social gatherings and crowds and avoiding bars as effective prevention measures. And to get through this pandemic at your healthiest, don't miss these 37 Places You're Most Likely to Catch Coronavirus.

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