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1) It's not uncommon to recover from COVID, test negative, and then test positive again down the line. Happened to ~1 out of 5 recovered patients in large China study (preprint.)
Reason was not re-infection: after testing negative, many tested positive while in quarantine...
Reason was not re-infection: after testing negative, many tested positive while in quarantine...
2) Also, 23 of those who retested positive (after testing negative) had interactions with over 96 others, but none of the 96 got the virus. That suggests the 21 had cleared the virus and were no longer infectious, despite testing positive again...
3) That's also supported by the fact that researchers couldn't recover the live virus from people who were retesting positive. Bits and pieces of the RNA genome of the virus was present, but live virus couldn't be cultured...
4) So recurring +'s don't necessarily mean re-infection & don't necessarily mean you're of risk to others. Could be that the virus is gone but fragments linger in an unstable way so the 1st test doesn't pick them up, but the 2nd one does. https://www.medrxiv.org/content/10.1101/2020.07.21.20125138v1
