April 16, 2020 / Alexandra Sternlicht, Forbes Staff TOPLINE – In China and South Korea COVID-19 survivors are retesting positive for the virus, further complicating the issues of post-recovery immunity and test validity. KEY FACTS 141 COVID-19 survivors in South Korea have retested positive for the disease—the Korean Center for Disease Control and Prevention (KCDC) is investigating the cause—uncertain whether the …