The new coronavirus has infected more than 13 million people worldwide. But can they get the virus again?
It seems that every day there is a new story about a person who is diagnosed with COVID-19 infection a second time. Last week, a New Jersey doctor claimed that two of his patients contracted the virus again, just two months after recovering from their initial infection. Similar stories have circulated across the country, prompting people to wonder if they really are safe from reinfection after an initial attack with the disease.
So far, experts say these anecdotes do not amount to definitive proof.
“It certainly is not cause for alarm,” said Dr. William Schaffner, professor of preventive medicine and infectious diseases at Vanderbilt University Medical Center. “We have anecdotes in which the scientific basis is partial, but in reality it is not tied to a pretty red bow. It is not complete “.
Now experts are struggling to understand how long people are protected from infection after they have already recovered from COVID-19.
Infection with COVID-19, or any virus, causes the body to activate the immune system to attack the active virus directly and also creates antibodies, some of which can help protect us against future infections.
PHOTO: A health worker performs a COVID-19 test at a Test Iowa site at Waukee South Middle School on July 14, 2020, in Waukee, Iowa. (Charlie Neibergall / AP)
Scientists still don’t know for sure whether it is possible for people to become infected a second time, but two recent studies, one from China and the other from the UK, found that the antibodies fighting future infections faded within a few months.
The first study, from Wanzhou, China, and published in Nature Medicine, found that neutralizing antibodies faded quickly, after just eight weeks, in both symptomless and symptomatic people. And a study published by King’s College in London, which has not yet been peer-reviewed, found that the neutralizing antibody response may begin to decline only three to four weeks after COVID-19 symptoms initially arise. The study also found a longer-lasting antibody response in patients with more severe symptoms.
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Although these recent studies have hinted that our antibodies may drop faster than many expected, experts say the antibodies are not the full story, and it is possible that other parts of the immune system may still offer some level of protection.
“The duration of immunity is unclear, but it makes sense that we can begin to see cases of reinfection with the new coronavirus, as with other common coronavirus infections,” said Dr. Todd Ellerin, director of infectious diseases at South Shore Hospital. . In theory, given enough time after recovery, reinfection is “plausible,” he said.
The new coronavirus, or SARS-CoV-2, belongs to a large family of coronaviruses known to cause diseases ranging from the common cold to serious infections, such as severe acute respiratory syndrome or SARS.
According to research on other coronaviruses, experts say there is a wide range in terms of the duration of immunity after an initial infection. For several of the coronaviruses that cause the common cold, the previous infection can protect you for about six to 12 months. However, other types of coronaviruses, such as Middle East Respiratory Syndrome or MERS virus, can result in several years of immunity.
Given this variation, there is ongoing research to determine if the virus that causes COVID-19 will behave more like MERS or more like the common cold.
Experts warn that immunity against a viral infection is a complex and multiple process. Although the exact duration of immunity after COVID-19 infection has not yet been determined, reinfection may occur.
PHOTO: A subject receives an injection in the clinical trial of the first-stage safety study of a possible Moderna vaccine for COVID-19, the disease caused by the new coronavirus, at the Kaiser Permanente Washington Health Research Institute in Seattle, FILE. . (Ted S. Warren / AP, FILE)
That means even people who have recovered must exercise caution, practice social distancing, wear masks, and wash their hands, according to the Centers for Disease Control and Prevention.
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“Having it once doesn’t give you free reign to go out and act like there’s no coronavirus around. I think we still need to take precautions because there are still so many things we don’t know, “said Dr. Simone Wildes, infectious disease physician at South Shore Health.
Although recovery after confirmed coronavirus infection “certainly provides short-term immunity”, people “should not change [their] Infection prevention behaviors, “Ellerin said.” Reinfection at some point in the future remains a possibility. “
Experts agree that we won’t know if reinfection is possible until the virus has been with us for years, rather than months. But with more than 13 million confirmed cases worldwide and limited anecdotes of possible reinfection, there have been no large-scale reinfection series so far, a somewhat reassuring sign.
“We don’t know if COVID will follow the same pattern” as other coronaviruses, Schaffner said, but “it wouldn’t surprise many people” if it did.
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