The World Health Organization (WHO) said that the people who recovered from Covid-19 may get it again, saying it is rare but possible.
A previous Hong Kong study suggests that people who have recovered from Covid-19 could be reinfected. It revealed what seems to be the first documented case of coronavirus reinfection. It involves a 33-year-old man, who initially got infected in late March and then again about four and a half months later, based on a STAT News report.
“It doesn’t mean that it’s happening a lot; we know that it’s possible,” Maria Van Kerkhove, head of the WHO’s emerging diseases and zoonosis unit, said during a live Q&A session. “It is something that we knew could be possible based on our experience with other human coronaviruses.” She reiterated that how long one's immunity lasts remains unknown.
“This is one example out of 23.5 million cases so far, but we expect that people who are infected do develop an antibody response, they do develop an immune response that lasts for some time, so we’re learning,” she said regarding the Hong Kong case.
Van Kerkhove explained that whether someone has been infected or not, they must observe recommended social distancing guidelines, wear face coverings, and follow other health precautions.
“Yes, it’s possible that we could start to see reinfection, but you know we have the tools in place that can prevent people from getting infected,” Van Kerkhove said.
“People think, ‘Oh, this means a vaccine won’t work.’ That’s not what this means,” she said. “We’re still developing vaccines, and there’s incredible progress being made on this.”
Immune protection
The case highlights the concerns about the durability of immune protection from the coronavirus. However, scientists presented broader concerns about reinfection.
Reports on Covid-19 reinfection have sprung from anecdotal evidence and are believed to be caused by flaws in testing.
In the case of Hong Kong, the new Covid-19 reinfection report was studied by researchers at the University of Hong Kong. They sequenced the virus from the patient’s two infections. Results showed that they did not match, suggesting that the second infection was not associated with the first. A difference of 24 nucleotides—the “letters” that make up the virus’ RNA—between the two infections was identified.
“This is the world’s first documentation of a patient who recovered from Covid-19 but got another episode of Covid-19 afterwards,” the researchers said in a statement.
“The fact that somebody may get reinfected is not surprising,” said Malik Peiris, a virologist at the University of Hong Kong, who is not an author of the paper describing the reinfection but has knowledge of the case.
“But the reinfection didn’t cause disease, so that’s the first point. And the second thing is that it is important to know whether the patient mounted a neutralizing antibody response to the first infection or not. Because the vast majority of patients in our experience do mount a good neutralizing antibody response. So is this person an outlier or is he likely to be the average person infected?”
