I’m not OP, just a concerned parent who is trying to figure things out. I have not been able to locate a single scientific study about this. Rather, the evidence all seems to be news reports of people testing positive, then negative and then positive again. Since it isn’t scientific, all the usual caveats apply - we don’t know much about how effective those tests were and again, these are news reports.
If you’re interested, I can post some news reports. Forbes actually has a pretty good rundown of the various news articles, but Forbes isn’t always the best place for facts or safe browsing, so I’ll avoid posting that one. In the interest of fairness, I can also post (much older) news reports that called HIV/AIDS “Gay Related Immuno-deficiency” and we know how good that science was.