I wouldn't read too much into this yet. Coronavirus tests are notoriously flaky and Korea has thousands of recovered people, so it's entirely possible that people either get false negatives twice (so they appear cured but aren't), or get true negatives followed by a false positive later (so they appear sick but aren't).<p>If there are patients who test negative for several weeks but <i>then</i> relapse and get clinically sick with COVID-19, we'll have cause to worry. On the other hand, if this was a common phenomenon, it'd be happening in China already.