A man in Hong Kong, who had recovered from coronavirus—contracted the infection again four-and-a-half months later in the first documented instance of human re-infection, Hong Kong University’s researcher said on Monday.
The research shows the indication that the disease, which has killed more than 800,000 people globally, may continue to proliferate amongst the global population despite herd immunity, they said.
The 33-year-old man was cleared of the coronavirus infection and discharged from a hospital in April, but after returning from Spain via Britain on Aug. 15, he contracted the disease again.
The patient had appeared to be previously healthy, researchers said in the paper, which was accepted by the international medical journal Clinical Infectious Diseases.
The patient was found to have contracted a different COVID-19 strain from the one he had previously contracted and remained asymptomatic for the second infection.
“The finding does not mean taking vaccines will be useless,” according to Dr. Kai-Wang — one of the leading authors of the paper said.
“Immunity induced by vaccination can be different from those induced by natural infection,” To said. “[We] will need to wait for the results of the vaccine trials to see if how effective vaccines are.”
Meanwhile, World Health Organization (WHO) epidemiologist Maria Van Kerkhove said on Monday that there was no need to jump to any conclusions in response to the Hong Kong case.
Instances of people discharged from hospitals and testing positive again for COVID-19 infection have been reported in 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.