South Korean health authorities are investigating possible interpretations of the cases of a few but growing, cured Covid-19 patients who are later diagnosed with coronary heart disease.
Among the many possibilities are the re-infection, recurrence or inaccuracy of diagnostic tests, according to experts.
South Korea has recorded 141 such incidents to date, according to the Korean Centers for Disease Control and Prevention (KCDC).
Re-infection or relapse?
Although re-infection would be the most worrying scenario, due to complications in population development, both KCDC and many experts say it is unlikely.
In contrast, KCDC tends to trigger a recurrence or “reactivation” of the virus.
Recurrence can mean that parts of the virus go into a kind of latent state for a while, or that some patients may have the disease or have a weakened immune system that makes it possible for the virus to revive in their body, according to experts.
Recent research by doctors in China and the United States has shown that the new colon may affect T lymphocytes, which play a central role in the immune system and its ability to fight the virus.
Kim Yeong-ki, a biologist at Korea University College of Pharmacy, has relapsed after recovery with a spring that returns after pressure.
“When you push a spring, it gets smaller, when you take your hands, the spring comes back.”
Even if patients are found to have relapsed rather than become re-infected, this will mean new complications in the spread of the epidemic.
“South Korean authorities have not yet identified cases where patients with ‘reactivated’ infection have transmitted the coronavirus to others, but if such transmission is proven, it will cause huge problems,” warns Seol Dai-wu, a vaccine development specialist. Professor at Chung-Ang University
The limits of diagnostic tests
Patients in South Korea are considered clean from the virus when they have negative results twice in a period of 48 hours.
While RT-PCR tests used in South Korea are generally considered accurate, experts say there are chances of erroneous or inaccurate results in a limited number of cases.
“RT-PCR tests are 95% accurate. That means there will still be 2% to 5% of cases where the results will be incorrectly negative or incorrectly positive,” says Kim Yeong-ki.
Residues of the virus may remain too low to be detected by the test, “he said.
On the other hand, tests can be so sensitive that they detect low, potentially harmless, levels of the virus, leading to new positive results, even if the patient has been cured, KCDC Deputy Director Kwon Jun- said a few days ago. wook.
The reliability of the tests can also be questioned if the necessary samples have not been taken correctly, according to Eom Joong-sik, a professor of Infectious Diseases at Gachon University Gil Medical Center.