South Korean infectious disease experts have downplayed concerns that patients could get reinfected with the new coronavirus after fully recovering.

While hundreds in South Korea have tested positive again after their release from hospitals, Oh Myoung-don, who heads the country’s central clinical committee on new infectious diseases, told a news conference on Wednesday there was a "high possibility" that such test results were flawed.

He said South Korea’s standard real-time Polymerase chain reaction (PCR) tests, designed to amplify the genetic materials of the virus so that even tiny quantities are detected, doesn’t reliably distinguish between remains of dead virus and infectious particles. He said lab tests on animals suggest that COVID-19 patients would maintain immunity for at least a year after their infections.

He also said it was unlikely that the virus could be reactivated after remaining dormant when it doesn’t seem to be a type that causes chronic illnesses.

As of Tuesday, 277 people in South Korea tested positive for the virus for a second time after being diagnosed as recovered. Health authorities have tested some of their samples, but none so far have been successfully cultivated in isolation, indicating a loss of infectiousness.