South Korea’s Centers for Disease Control and Prevention (KCDC) recently conducted a study of nearly 300 COVID-19 patients, concluding that these new coronary patients are not contagious. KCDC explained that these patients are not contagious and that although some of them develop symptoms, they are immune to the disease. KCDC reported in mid-April that hundreds of patients had tested positive again. The medical authority observed changes in patients with the new coronary fuyang in the following weeks and delivered the best preliminary information about the reinfection of the coronavirus, which is not a recurrence.
KCDC officials published the results of the study online, showing that it investigated 285 “fuyang” cases and 790 contacts. Of these, 27 contacts tested positive, 24 of them in previously confirmed cases. The other three were cases of contact with religious groups, or in their families, so it is likely that people other than “reinfected people” have been infected.
The study said it took an average of 45 days, or 14.3 days, from the initial symptoms to the second positive. As many as 44.7 percent of patients had symptoms including coughing and sore throats, the report said. Sixty percent of them were screened and tested regardless of the symptoms. Doctors have also found neutralizing antibodies in all cases of fuyang and in newly diagnosed cases, a marker of COVID-19 immunity.
KCDC concluded that, based on the available evidence, the case was not contagious. In addition, KCDC revised its policy on patients who tested positive again, eliminating the 14-day recommendation for self-isolation, and the requirement for new COVID-19 testing for those patients. Fuyang cases will still be reported and counted and their contacts will continue to be investigated.
“So far, we have not seen a secondary infection in people who have been exposed to Fuyang patients, ” said Nguyen Tae-hyun, a senior south Korean health ministry official, at the briefing. The Wall Street Journal reported that KCDC will stop using the term “recurrence” to refer to these patients. Instead, they say the new coronavirus in some patients has been “rediscovered.” More patients are likely to re-test in the future.
The most likely explanation for this phenomenon is that the high-precision COVID-19 RT-PCR detector used in South Korea detected fragments of the dead virus after the patient recovered, resulting in false positives.
“We are more concerned with the theory that fragments of the dead virus remain in the bodies of recovering patients because we have not seen any evidence of infection,” said Ki Moran, a handler at the National Cancer Center in South Korea.
KCDC will continue to monitor these cases, but this preliminary data is good news for the rest of the world. The immunity of the new coronavirus is still something to be explained. Doctors are still unable to provide an estimate of immunity. More durable COVID-19 immunity will be good news for those who survive, as well as future vaccine candidates. Until then, KCDC studies have at least shown that patients are less likely to be infected with COVID-19 for a second time in the weeks after the first diagnosis.
South Korea has effectively controlled the spread of COVID-19 in its home country. Through active detection and contact tracing, the authorities were able to significantly reduce the spread of the disease and flatten the curve early on. More than 11,000 cases have been reported in the country since January, and as of Tuesday afternoon, 263 people had died.