Reinfection unlikely among COVID-19 patients, say experts

Reinfection unlikely among COVID-19 patients, say experts

Reports of discharged patients testing positive for coronavirus believed to be connected to testing errors or unresolved cases

A microscopic 3D rendering of coronavirus, a pathogen that attacks the respiratory tract. (Naeblys/iStockPhoto)
A microscopic 3D rendering of coronavirus, a pathogen that attacks the respiratory tract. (Naeblys/iStockPhoto)

While the medical community is still struggling to fully understand the novel coronavirus that causes COVID-19, there appears to be an emerging consensus that despite reports of victims catching the disease twice, becoming reinfected after recovering is actually highly unlikely.

Time magazine on Friday cited reports of cases of victims testing positive for the virus after being successfully treated and discharged from hospitals in several Asian nations, including a recent Chinese study of recovered patients in Shenzhen in which nearly 15 percent of discharged patients tested positive for coronavirus.

Time said, though, that these patients were mostly asymptomatic and that other preliminary research indicated that monkeys exposed to the disease had developed antibodies that prevented them from becoming infected again upon reexposure.

Experts who spoke with the US publication, as well as several other media outlets, said emerging data indicates that either the cases in question had not been fully resolved or that the discrepancies were due to insufficiently sensitive tests offering false positives.

A body wrapped in plastic that was unloaded from a refrigerated truck is handled by medical workers wearing personal protective equipment due to COVID-19 concerns at Brooklyn Hospital Center in the Brooklyn borough of New York, March 31, 2020. (AP/John Minchillo)

Some of those who were retested may have appeared to still be infected because “of the quality of the specimen that they took and maybe because the test was not so sensitive,” Professor David Hui of the Chinese University of Hong Kong told Time.

“Viral RNA can last a long time even after the actual virus has been stopped” and could account for such cases, he said.

“We simply don’t know yet because we don’t have an antibody test for the infection, although we will have soon,” Professor Jon Cohen of Brighton and Sussex Medical School told The Guardian last month when asked about reinfection.

“However, it is very likely, based on other viral infections, that yes, once a person has had the infection they will generally be immune and won’t get it again,” he said. “There will always be the odd exception, but that is certainly a reasonable expectation.”

One expert did tell the British paper that while there was “some evidence in the scientific literature for persistent infections of animal coronaviruses (mainly in bats),” it was “unlikely” that people did not develop immunity to the coronavirus following their recovery.

Illustrative: Magen David Adom workers and a Shaare Zedek hospital medical team, wearing protective clothing, as a preventive measure against the coronavirus in Jerusalem on April 2, 2020. (Nati Shohat/Flash90)

“The tests used to determine if someone is infected rely on detecting tiny fragments of genetic material from the virus,” reported Ars Technica, an American science and technology publication.

“While this is a good indication that someone has been infected, it doesn’t necessarily indicate that an infection is active or the genetic material is from an intact, infectious viral particle. The tests may simply be picking up genetic remnants of a past infection,” it said.

But while the consensus appears to be that people are unlikely to become reinfected, given the current state of knowledge about the new virus, “it’s still unclear how long that immunity might last.”

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