Alarm bells were raised when hundreds of recovered COVID-19 patients in South Korea, China, and Japan appeared to test positive again. Such results questioned the improbability of immunity after recovering from the deadly virus and riddled holes into plans of assigning "immunity passports" in countries about to ease their restrictions.
However, the South Korean Center for Disease Control and Prevention says that it is impossible for the COVID-19 virus to reactivate in human bodies, reports Sky News on May 1.
According to the report, "the polymerase chain reaction (PCR) test used to check the blood for antigens—actual particles of the virus itself—could also have issues." The South Korean CDC stated that the tests yielded false positives for relapsed patients since they could not distinguish between live traces of the virus and the dead samples that remain in the body after recovery.
Carol Shoshkes Reiss, professor of Biology and Neural Science at New York University, confirmed this likelihood to Live Science: "Although somebody can recover and no longer be infectious, they may still have these little fragments of [inactive] viral RNA which turn out positive on those tests."
Reiss is not involved in any COVID-19 testing.
According to Reiss, a different type of test is required to check if a person has actually been reinfected with the novel coronavirus. "Lab technicians would have to culture it, or place that virus in a lab dish under ideal conditions and see if it was capable of growing," she explained.
The surge of supposedly reinfected patients all over the world has prompted the World Health Organization end of April to announce that there's been no evidence to support that COVID-19 survivors will not get reinfected.