According to the health organization, people who tested positive for the second time after recovering are not getting reinfected but are still expelling dead lung cells rather than getting a new infection.
This comes after South Korean health authorities raised fresh coronavirus concerns after reporting more than 300 cases of recovered patients who later tested positive again.
‘We are aware that some patients test positive after they clinically recover,’ a WHO spokesperson told AFP, without making specific reference to the South Korean cases.
‘From what we currently know – and this is based on very recent data – it seems they these patients are expelling left over materials from their lungs, as part of the recovery phase.’
An expert in virology told MailOnline that once the virus is inactivated by the immune system and forms a complex bond with an antibody, it stops being infectious but can still be detected by a swab test.
WHO spokesperson also admitted that it was still not clear whether the body builds up enough immunity to ward off a new attack by the virus and if it does, how long such immunity lasts.
‘We need systematic collection of samples from recovered patients to better understand how long they shed live virus,’ the WHO spokesperson said.
‘We also need to understand if this means they can pass the virus to other people – having live virus does not necessarily mean it can be passed to another person.’
The organization added that more research is needed on the recovered patients who originally tested negative and then tested positive weeks later.
In a recent interview with BBC, infectious disease epidemiologist Maria Van Kerhove, explained the ‘dead cell’ in the lungs.
‘As the lungs heal, there are parts of the lung that are dead cells that are coming up,’ she said, talking on The Andrew Marr Show on Sunday.
‘These are fragments of the lungs that are actually testing positive.
‘It is not infectious virus, it’s not reinfection, it’s not reactivation – it is actually part of the healing process that is being captured again as being positive.
‘Does that mean they have immunity? Does that mean they have a strong protection against reinfection? We don’t know the answer to that yet.’