Can you catch coronavirus twice? This is an issue that might influence the evolution of the epidemic, especially as it comes to herd immunity. As of today, it is still not certain, but doctors have reported two cases of SARS-CoV-2 re-infections in the medical literature.
The first case studied and reported in the literature is of a 33-year-old Honk-Kong man who was carrying two instances of the SARS-CoV-2 virus, in four months and a half apart. Sick and positive first in March, he has tested positive again in August when being tested at the airport when returning from a trip to Spain via the United-Kingdom. He was asymptomatic.
The second case has just been reported by searchers from the Nevada University. The 25-year-old man has tested positive back in April, then negative, before falling sick again 48 days laters. Searchers have sequenced the genome of the virus and say “two instances of SARS-CoV-2 infection in the same individual […], the viruses associated with each instance of infection were found to possess a degree of genetic discordance”.
As a matter of fact, coronavirus re-infection is no easy task to establish. Since the health crisis broke out, supposed cases of new infection in people who already caught coronavirus have been reported in the news, but are raising questions on the mutation of the virus in vivo, that is to say within the body of the patient, reliability of tests and reactivation of the virus.
In reply to these concerns, searchers are doubling up samples taken in order to avoid false negative as much as possible, and now investigate the genome of the virus. We know it, there are several instances of the SARS-CoV-2 coronavirus depending on the area across the world. Each "clade" has its features and mutates over time. These features enable searchers to know if this is a reactivation of the virus or a likely mutation of the virus.
Even though, until August, there have been no real Covid-19 reinfection case officially reported as such, cases are starting to show up with in-depth studies letting us think about real reinfections. As for Doctor Jeffrey Barrett from the Wellcome Sanger Institute says : "Given the number of global infections to date, seeing one case of reinfection is not that surprising".