As far as I know none of our leaks have been by releasing an infectious person after a negative test result.
It’s possible for PCR tests to return negative for a very early (low viral load) infection though; that’s why for high-risk travellers we do PCR tests on days −3, 1, 5, 11, and 14 of the quarantine period. For low-risk settings, ie contact tracing, you only need to isolate until you get a negative PCR test result.
As far as I know none of our leaks have been by releasing an infectious person after a negative test result.
It’s possible for PCR tests to return negative for a very early (low viral load) infection though; that’s why for high-risk travellers we do PCR tests on days −3, 1, 5, 11, and 14 of the quarantine period. For low-risk settings, ie contact tracing, you only need to isolate until you get a negative PCR test result.