Up to a third of people who tested positive for SARS-CoV-2 by Polymerase Chain Reaction (PCR) tests were not contagious and did not need to self-isolate, according to a new study.
Research led by academics from the University of Oxford found that many UK laboratories are setting the positivity bar very low, meaning they are picking up people who are “a danger to no one.”
Freedom of Information requests made by members of the public show that National Health Service (NHS) trusts are using vastly different cut-off cycle thresholds, with little regulation from the government. Some are as low as 25, while others are as high as 45.
Dr. Tom Jefferson, co-author and an epidemiologist at the Centre for Evidence-Based Medicine at the University of Oxford, said: “We found that about one-third of people who isolated probably didn’t need to.”
“PCR positivity means that you can tell people to isolate and ruin their lives basically, even though in a large proportion of these cases, they are not infectious.”
“It’s absolute chaos. The whole regulation of these tests seems to be shambolic,” he said.
Professor Carl Heneghan, director of the Centre for Evidence-Based Medicine at the University of Oxford, said: “It’s deeply worrying. When you have more virus circulating in the community, the potential for contamination is greater. Studies have shown that people can be easily contaminated with a viral fragment.”
“The problem is the panic of the pandemic meant that we developed policies at a speed we’ve never seen before and we haven’t looked at them to find out which are evidence-based.”
“Accurately knowing who is infectious is incredibly important for people going about their daily lives, the economy, our social lives and our wellbeing. The impact on the economy is now coming home, and it is clear that we cannot afford to keep isolating people,” he added.