In an interesting development, a 33-year-old man has tested positive for COVID-19 twice within a time span of 4.5 months.

According to a CNN report, the patient got infected by the virus for the first time on March 26. At that time, he had cough, sore throat, fever and headache for three days.

He reportedly got infected for the second time while heading back home from Spain. He tested positive while he was screened at the Hong Kong airport on August 15.

The report quoted Dr. Kelvin Kai-Wang To of the University of Hong Kong as saying, "The patient got re-infected 4.5 months after the first infection. Therefore, it shows that for this patient, the immunity induced by the first infection is short lasting."

The CNN report also quoted a team of researchers at the University of Hong Kong  as saying, "This case illustrates that re-infection can occur even just after a few months of recovery from the first infection. Our findings suggest that SARS-CoV-2 may persist in humans, as is the case for other common-cold associated human coronaviruses, even if patients have acquired immunity via natural infection or via vaccination."