A recent article published in The Lancet medical journal explains that PCR tests can be “positive” for up to five times longer than the time an infected person is actually infectious.

Arjun Walia. New Lancet Article Suggests 50-75% of “Positive” PCR Tests Are Not Infectious People. Collective Evolution. 03 March 2021. https://www.collective-evolution.com/2021/03/03/new-lancet-article-suggests-50-75-of-positive-pcr-tests-are-not-infectious-people/.