Explainer: Why are some South Koreans who recovered from the coronavirus testing positive again?

FILE PHOTO: The "N Seoul Tower" is seen in the background as people wearing face masks sit inside a bus, as part of efforts to avoid the spread of the coronavirus disease (COVID-19), in Seoul, South Korea, April 7, 2020. REUTERS/Kim Hong-Ji

SEOUL (Reuters) - South Korean health officials are investigating several possible explanations for a small but growing number of recovered coronavirus patients who later test positive for the virus again.

Among the main possibilities are re-infection, a relapse, or inconsistent tests, experts say.