Researchers from the University of Hong Kong reported what could be the first documented confirmed case of coronavirus reinfection, as a man from Hong Kong tests positive for the virus again after he contracted the virus in March. The 33-year old IT worker from Hong Kong was diagnosed with covid19 in March with usual covid19 symptoms and was discharged by the hospital in April when he recovered from the disease but after nearly 142 days of his first infection, he tests positive again, this time with no obvious symptoms.
The study by the University of Hong Kong has been accepted by the Journal ‘Clinical Infectious Diseases’ for publication. During the first diagnosis, the patient had the symptoms of sore throat, headache, fever, and cough, and tested positive on the 26th of March, according to the study. The man tested positive again on the 15th of August during his entry screening at the Hong Kong airport when he was returning from Spain via the United Kingdom. He was immediately admitted to the hospital but showed no symptoms.
Experts believe that the finding of this coronavirus reinfection case was not unexpected as millions of people around the world are infected already. As the man had no symptoms the second time, it suggests that the prior exposure to the virus did not prevent the person from getting infected again but instead his immune system kept him from getting severely ill.
An immunologist at Yale University Akiko Iwasaki, who was not a part of the research but reviewed the report, said that the second infection was completely symptomless and his immune response prevented the disease from getting worse. She described it as a textbook example of how the immunity should work.
Several presumed cases of coronavirus reinfection have been reported by doctors in the United States and elsewhere, however, none of these cases were confirmed through testing. People who have recovered from the virus are known to contain viral fragments from the virus for weeks, which may lead to a positive test result even in the absence of the virus.
In this case, however, the researchers from Hong Kong have sequenced the virus from both infections and have discovered significant differences in the two which suggests that it is a case of reinfection. A clinical Microbiologist at the University of Hong Kong Dr. Kelvin Kai-Wang To said that he believes that this is the first reported case of reinfection confirmed by genome sequencing. He further said that the results prove that his second infection is caused by a new virus acquired recently rather than prolonged viral shedding.
Genetic Analysis from the study showed that the first infection was caused by a strain of the covid19 resembling the strains from the US or England and the second infection most closely resembles strains from England or Switzerland.
The researchers wrote that this case of coronavirus reinfection illustrates that reinfection can occur just after months of getting recovered from the first infection. The findings from the study suggest that SARS-CoV-2 may persist in people, as with the case for other common-cold associated human coronaviruses, even if the patients have acquired immunity via vaccination or natural infection. The findings also suggest that even if you have recovered from the virus you should get yourself vaccinated when the vaccine becomes available.