Those who had Covid19, may have contracted the virus again is the new head ache of South Korea. A patient once saved from the coronavirus attack was considered almost safe until now. But South Korea is currently facing the issue of reinfection of the virus in patients who recovered from the virus attack earlier.
But the country is now grappling with a new problem: at least 222 people have tested positive for the virus again after recovering, and experts are not sure why. Experts believe it might be a matter of how an individual's immune system functions. Some patients who had been infected with COVID-19 might experience a "relapse" because of other underlying health conditions and weak immune systems. Researchers also think that some patients might still be carrying the virus for longer than the expected 14-day period.
"We can look at this as a matter of reinfection or a matter of reactivation," said Dr Roh Kyung-ho, who works at the Department of Laboratory Medicine at the National Health Insurance Ilsan Hospital.
Considering the South Korean example, the difference between those two words - reinfection or reactivation - could be key in the global fight against COVID-19.
Simply put, a reactivation would mean that an individual with COVID-19 has not been able to fight off the virus after seeming to get better. Being reinfected would mean that an individual has fully recovered but then contracts the virus again.
"It is most likely that the virus is reactivated or reinfected because of [an individual's] insufficient immune function," Roh explained. "In the case of reinfections, it's possible that a person recovers from the virus and then comes into contact with other asymptomatic carriers of the virus in the community."
Only eight new cases of the virus were confirmed in South Korea between April 22 and 23, just under two months after what then appeared to have been the peak of the outbreak on February 29 when the country reported the world's most infections outside China.
But with about 78 percent of those who once tested positive now cleared and released from quarantine, researchers remain unsure about the possibility of those who once had COVID-19 contracting it again.
Experts in South Korea do not seem to think the fault lies with their test kits, which are now being exported en masse. At least 120 countries have requested Korean COVID-19 tests as imports or humanitarian aid, while South Korea exported test kits worth $48.6m in March.
"Given the high accuracy of test kits and volume of testing being conducted, this many cases of reinfection or reactivation is not a high number," he added.
About 20 percent of those known to have gotten sick again are in their 20s, with those in their 50s making up the second-largest group of those who either relapsed or were reinfected.
So far, early research from doctors in China and the US suggests that the coronavirus might be damaging lymphatic organs, or T-lymphocytes, the cells that help maintain a healthy immune system.