Reinfected. When all this first started going, there was conversation about reinfection.

[TwilightZone]

1. Some scientists think it's human error or false results.

"Scientists in and outside China agree that reinfection is a highly unlikely explanation for the patients who retest positive. They say testing errors are more likely to blame — either false negatives that resulted in patients being discharged too early, or false positives when they retested and were taken back into hospital.

Those errors could be attributed to contaminated test samples, human error while taking swabs, or an oversensitive nucleic acid test that detects strands of virus. When a person gets sick with any kind of viral infection, their immune system naturally develops antibodies that should protect them from contracting the illness again after they’ve recovered.

Even in cases where that immunity wears off, it shouldn’t be as quick as within a few days or weeks, said Dr. Keiji Fukuda, director of Hong Kong University’s School of Public Health.

“If you get an infection, your immune system is revved up against that virus,” he said. “To get reinfected again when you’re in that situation would be quite unusual unless your immune system was not functioning right.”"

https://www.latimes.com/world-nation/story/2020-03-13/china-japan-korea-coronavirus-reinfection-test-positive