University of Hong Kong researchers have reported a case of a man who recovered from Covid-19 and got infected again four-and-a-half months later. Researchers say it was a different strain.
The man, 33, was released from a hospital in April but reportedly tested positive for Coronavirus again in August, this time with no symptoms, after returning from a trip to Spain.
The case is reportedly included in a paper in Clinical Infectious Diseases.
The Hong Kong University researchers call the case "the first documented instance of human re-infection." Some experts say previous reports of reinfection were likely in patients who simply had not cleared the virus the first time.
One researcher suggests reinfection is "not that surprising" and a "very rare occurrence."
It's unclear as to whether vaccines in development would protect patients from all strains of coroavirus, and for how long.
Instances of people discharged from hospitals and testing positive again for COVID-19 infection have been reported in mainland China. However, in those cases it was not clear whether they had contracted the virus again after full recovery - as happened to the Hong Kong patient - or still had the virus in their body from the initial infection.
Read more below: