South Korea reported its first case of coronavirus re-infection on Saturday, February 29. Previously, Japan, Israel and China have reported similar cases of a fully-recovered person getting re-infected with the deadly virus.

Coronavirus re-infection cases

Before South Korea, Israel reported that a fully-recovered patient was re-infected with Covid-19. Shimon Dahan, an Israeli national, tested positive on-board the Diamond Princess cruise ship quarantined near Japan's capital Tokyo, returned to Israel on Tuesday, February 25 after having fully recovered. On Friday, he tested positive, The Jerusalem Post reported.

A Chinese patient, known by his surname Wang tested positive on January 26. He left the hospital on February 9 and was quarantined for an additional two weeks. On Friday, he was reported re-infected with the novel coronavirus, Daily Mail reported.

Japan also reported that an Osaka woman, who recovered after being infected late in January, tested positive for a second time. Song Tie, vice-director of the local disease control centre in China's Guangdong province, said on Wednesday that about 14 percent of discharged patients in the province tested positive.

What might be the reason behind coronavirus reinfection?

According to reports, fully recovered patients may not have developed immunity to Covid-19. Not much is known, whether antibodies developed in recovered patients are strong enough to protect him/her from being re-infected. Another possibility is that the virus subsided and flared up again, i.e., the virus could be 'biphasic', which means, it lies dormant before showing new symptoms. Also, testing discrepancies might display wrong results, Wired reported.

A study published in the Journal of the American Medical Association (JAMA) stated that recovered patients can still remain virus carriers, even after meeting discharge criteria. However, according to reports, none of the re-infected patients have infected others, which is a good sign.

Till now, 39,332 patients have recovered. If the re-infection rate is pegged at 14 percent as in China's Guangdong province, this raises serious alarm about the epidemic being far from over. As on Saturday, more than 85,000 people in over 60 countries have been infected with the novel coronavirus. More than 2,900 have died due to the disease.