Since follow-on PCR tests were more likely to be positive than other PCR tests, this policy change may initially lead to a fall in the positivity rate.
Gan fod profion PCR dilynol yn fwy tebygol o fod yn bositif na phrofion PCR eraill, gallai’r newid polisi hwn arwain at ostyngiad yn y gyfradd bositifedd i ddechrau.