Scientists have reported the world’s first case of a human being re-infected with coronavirus in a discovery that could have significant implications for the development of vaccines and hopes if natural immunity against the virus.
Researchers at Hong Kong University’s department of microbiology said genetic sequencing of the virus showed a Hong Kong man was infected twice by different versions of the Covid-19 virus month apart.
Announcing the results, the university said: “An apparently young and healthy patient had a second episode of Covid-19 infection which was diagnosed 4.5 months after the first episode.”
It said there were two different lineages of the virus detected.
The full research has yet to be published and experts say its too early to jump to conclusions about what the single case might mean on a global scale.
But if the research, published in the medical journal Clinical Infectious Diseases, is correct then it could mean vaccines against the virus may not give permanent protection and people may not be able to rely on being immune to the virus after recovering from an infection.
Dr Jeffrey Barrett, from the Wellcome Sanger Institute, said: “It is very hard to draw firm conclusions from the press release alone. Some of the paper has been published on social media, which fills in some gaps, though we’re still waiting for the full paper.”
He added: “This is certainly stronger evidence of re-infection than some of the previous reports because it uses the genome sequence of the virus to separate the two infections. It seems much more likely that this patient has two distinct infections than a single infection followed by a relapse.
“An important point about this one case, which is not mentioned in the press release, is that the second infection is asymptomatic. It was caught by screening tests on returning passengers at HK airport, and the individual never developed any symptoms from their second infection.”
He said given the number of global infections so far, one case of reinfection was not surprising and he warned the research “implications” were too broad given it was based on one case.
“This may be very rare, and it may be that second infections, when they do occur, are not serious (though we don’t know whether this person was infectious during their second episode).”