The report by the South Korean authorities caused a sensation on Friday. 91 people who were already recovered and had been released from quarantine were again tested positive for the novel corona virus. The Korean Center for Disease Control (KCDC) believes that these are not new infections. It is more likely that the virus has “reactivated”, said KCDC boss Joeng Eun Kyeong. South Korean virologist Kim Woo Joo anticipated a further increase in “reactivated” coronavirus cases: “91 is only the beginning.” South Korea’s authorities and the WorldHealth Organization (WHO) immediately announced further investigations.
The phenomenon has so far been little researched, but not new: As early as February, the virus was detected by four doctors in China who had survived Covid-19 and had tested negative twice. 172 patients were examined in the Chinese metropolis of Shenzhen. In 25 of them, the PCR test was positive about a week after the last negative result. In Wuhan, physicians found five newly positive cases among 55 recovered people – in four of them, those affected had even developed mild symptoms such as fever, cough and sore throat, the “Zeit” reported.
South Korea is considered one of the international role models for CoV containment – now the pathogen apparently appeared again in those who were already healthy
There are many signs of immunity
The question of whether people recovering from an infection can become infected again with the coronavirus is of international importance. Many countries believe that people recovering from a CoV infection develop immunity to the virus and that over time a sufficiently large section of the population is immune to the disease to prevent the pandemic from flaring up again – keyword herd immunity.