Some Good News About COVID-19 From South Korea

Soon after the first patients began to recover during the initial outbreak of COVID-19 in Hubei Province, China, researchers in the area noticed something both peculiar and frightening. A portion of those who initially tested positive, then were sent home after receiving a negative test result, were turning up again with a positive test at a later date. These results, which in some reports were as high as 15% of patients, brought into question both the accuracy of tests and even the possibility of a vaccine. After all, if patients could catch COVID-19 over and over, it seemed unlikely any vaccine could provide protection.

That same effect—a patient tests positive, then negative, then positive again—has continued to appear around the world.  As Bloomberg reports, researchers at the Korean Centers for Disease Control and Prevention studied a group of 285 patients who had received at least one negative test result after recovering from COVID-19, then received a positive result at a later date. Their conclusion was that these “re-positive” patients were not only not contagious, but immune.

When samples of virus were taken from these patients, it would not reproduce in the lab. What was generating the positive result doesn’t appear to be live virus … but dead virus. So these patients had apparently developed an immune response that allowed them to fight off reinfection, and were not carrying virus that could infect others.

As a result of these tests, South Korean authorities will no longer require those who have tested negative after recovering from COVID-19 to take additional tests to confirm their status before returning to work, school, or travel. So far as researchers in South Korea are concerned, these people are not a threat. Not a threat to get COVID-19. Not a threat to spread it.