Dr. Cillian De Gascun:

It has been demonstrated that virus is culturable, that live virus is retrievable at a Ct of up to 37. It will not be recoverable in 100% of individuals with a Ct of 37 but it is recoverable at that level. We need to be very careful about just assuming a Ct of greater than 25 or greater than 30 is not infectious or does not contain viable virus. We do not yet know the infectious dose of SARS coronavirus type 2. Anybody who says they do and can correlate it with a Ct value is unfortunately misleading the committee.