Troubling headlines have been cropping up across Asia: Some patients in China, Japan and South Korea who were diagnosed with COVID-19 and seemingly recovered have been readmitted to the hospital after testing positive for the virus again.
[S]cientists are still trying to answer many big questions related to the virus and the disease it causes. Among them is whether patients can be reinfected by the virus after they seem to recover from the symptoms.
With other coronavirus strains, experts say the antibodies that patients produce during infection give them immunity to the specific virus for months or even years, but researchers are still figuring out if and how that works with COVID-19.
The answer has huge implications for the spread of the disease, since researchers believe it will continue to crash across the world in waves, hitting the same country multiple times
There remains a lot of uncertainty, but experts TIME spoke with say that it’s likely the reports of patients who seemed to have recovered but then tested positive again were not examples of re-infection, but were cases where lingering infection was not detected by tests for a period of time.