KATHMANDU: Hong Kong scientists have documented the first case of reinfection in a healthy man in his 30s four and a half months after his first bout, BBC reported.

There have been more than 23 million cases of coronavirus infection around the world. Those infected develop an immune response as their bodies fight off the virus which helps to protect them against it returning.

The strongest immune response has been found in the most seriously ill patients.

But it is yet to be investigated how strong this protection or immunity is – or how long it lasts.

The World Health Organization, however, has warned that it is important not to jump to conclusions based on the case of one patient.

It said larger studies over time of people who had previously had coronavirus were needed to find out more.

Similarly, experts say reinfections may be rare and not necessarily serious.

(With inputs from Agencies)