While there are many reports claiming that cured Coronavirus patients have tested positive for the second time even after receiving a treatment which clinically cured them, the World Health Organization has recently revealed that recent data showed that it seems these patients are expelling leftover materials from their lungs, as part of the recovery phase. The WHO clarified that it is not the case of reinfection.
It should be noted that South Korea officials reported over 100 such cases in April, raising concerns that patients who had recovered could become re-infected by the virus. Without making specific reference to the South Korea cases, a WHO spokesperson told AFP that "We are aware that some patients test positive after they clinically recover."
Why it is happening?
As per recent research materials, Coronavirus patients build up antibodies starting a week or so after infection or the onset of symptoms. But as per the experts, it is still not clear whether the body systematically builds up enough immunity to provide protection from a new attack from the virus. It is also not revealed that if it does then how long such immunity lasts inside the human body.
The WHO revealed that to understand why people who tested negative and weeks later again tested positive for COVID-19, more research is needed. The spokesperson told AFP:"We need a systematic collection of samples from recovered patients to better understand how long they shed the live virus."
In addition, he also stated, "We also need to understand if this means they can pass the virus to other people – having the live virus does not necessarily mean it can be passed to another person."
The 'dead cell' scenario
Recently while talking to BBC, infectious disease epidemiologist Maria Van Kerhove, who's part of the WHO Health Emergencies Program said, "As the lungs heal, there are parts of the lung that are dead cells that are coming up. These are fragments of the lungs that are actually testing positive. It is not an infectious virus, it's not reactivation. It is actually part of the healing process."
But the answers remain for questions such as --Does that mean they have immunity? or Does that mean they have strong protection against reinfection?
It should be noted that as per the experts, people once suffer from measles are immune for life, while for other Coronaviruses such as SARS, the immunity in the human body lasted from a few months to a couple of years.