The man had mild symptoms the first time and none the second time; her most recent infection was detected through screening and testing at Hong Kong airport.
“It shows that some people are not immune to the virus for life” if they have had it before, To said. “We don’t know how many people can be re-infected. There are probably others there. ”
The article has been accepted by the journal Clinical Infectious Diseases but has not yet been published, and some independent experts have called for caution until full results are available.
Whether people who have had COVID-19 are immune to new infections and for how long are key questions that have implications for vaccine development and decisions about returning to work, school and activities social.
Even though a person can be infected a second time, it is not known if they have some protection against serious illness, as the immune system usually remembers how to make antibodies against a virus it has seen before.
It’s unclear how different a virus must be to trigger disease, but the new work suggests that “COVID patients shouldn’t be content with prevention measures” and should continue to socially distance, wear masks and ‘other ways to reduce infection, To said.
Two experts having no role in the work agree.
“We always knew that reinfection was a possibility and I think this is very telling” that it happened in this case, said Dr. Jesse Goodman, former chief scientist of the US Food and Drug Administration. United now at Georgetown University. “If there is reinfection, it suggests the possibility that there was some residual immunity… which helped protect the patient” from new disease, Goodman said.
However, “if immunity wanes due to natural infection, this could be a challenge for vaccines” and may mean that booster shots are needed, he added.
Julie Fischer, a microbiologist at CRDF Global, a nonprofit health group in Arlington, Virginia, said the study gave compelling evidence that reinfection could occur.
“The real question is what does this mean for the severity of the disease” if this happens, and if these people can infect other people, she said.
One expert saw the report as good news. Dr Paul Offit, a vaccine expert at Children’s Hospital in Philadelphia, said he was encouraging the reported reinfection went without symptoms.
“It’s a victory for me” because it suggests that a first infection could protect a person from moderate to severe illness the second time around, he said in an interview with the Journal of the American Medical Association.
A survey conducted in mid-May by the physician information sharing site Sermo found that 13% of 4,173 responding physicians believed they had treated one or more re-infected patients. Among respondents, 7 percent of those in the United States and 16% in other countries believed they had seen such a case.
However, health officials have also questioned whether people who tested positive long after their initial illness were simply showing signs of not completely clearing the virus rather than becoming infected again.
PA medical editors Linda A. Johnson and Carla K. Johnson contributed to this report.
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