Despite this, a growing number of experts now say that PCR testing could have been scrapped completely in early 2021 as the vaccines were rolled out.
They say [PCR testing] was badly needed in 2020 to get a handle on soaring Covid deaths and stop people unknowingly passing on the virus, but by last summer, with the majority vaccinated, it was 'pointless'.
Dr Alexander Edwards, associate professor in biomedical technology at the University of Reading, acknowledges PCR tests 'aren't perfect' but adds: 'Yes, it can pick up tiny amounts of virus, but those who say that means it isn't enough to be infectious are missing the point.
'The argument about cycle thresholds and infectiousness is an unfortunate distraction,' he adds.
'The majority of people who test positive on a PCR, no matter how many cycles it has been through, are likely to be infectious. The best you can do is use a positive test as a red flag for likely infectiousness and ask people to stay inside.'