Late test results could make track and trace useless, ministers told
CORONAVIRUS tests taking longer than 48 hours to provide results risk rendering the track and trace system useless, experts have warned.
Up to 20,000 tests a day are taking longer than two days to process.
Scientists advising the Government predict this could lead to a 50 per cent increase in the number of infections.
It comes as a former World Health Organisation director called for GPS to help lead the test and trace system, with testing hubs at local surgeries.
Officials are unable to say how many tests have been completed within the optimal 24 hours recommended by the Scientific Advisory Group for Emergencies (Sage).
However, the Prime Minister has admitted that 10 per cent of tests, for which they have a target of 200,000 a day, are not completed within 48 hours.
Contrary to advice from scientific advisers, the contacts of a person with Covid-19 are only notified when a positive test result is returned
Dr David Bonsall, of the University of Oxford’s Nuffield Department of Medicine and an adviser to the NHSX app programme, said: “Even with a delay of 48 hours we predict that there is about a 50 per cent increase in the number of infections.” He told The Daily Telegraph that if from the moment someone displays symptoms “you wait 48 hours to get your test results in before you trace that individual’s contacts there is quite a high probability that they are likely to have infected someone else”.
Modelling by a number of institutions has shown that on average people take between five and six days to show symptoms and are infectious for around two days before that. Half of transmissions are said to occur before symptoms start, Dr Bonsall said, which was why it was essential to isolate infected people before they fell ill.
A study by the Data Evaluation and Learning for Viral Epidemics group, set up by the Royal Society, found “speed is of the essence” and contact tracing alongside other measures “reduces the number of new infections otherwise occurring by 5-15 per cent”.
The study – considered by Sage – notes that to achieve the upper end of the reduction, contact tracing needs to be reduced to three days. It adds: “Our simulation model finds that reducing the overall turnaround time from five days to three leads to 60 per cent greater reduction in R due to contact tracing of extra-household contacts”.
Meanwhile, Prof Anthony Costello, who formerly ran the WHO child health programme, called on the Government to make use of the existing primary care network in England.
“We have 1,300 primary care networks in England, for example, of GP surgery hubs, one for every 30,000 population,” he told Today on BBC Radio 4. “Why can’t we set up testing hubs there, with infection control nurses, courier the tests the same as you do for all your other ones, get them back the same day, have contact tracers linked to that system?”
Boris Johnson said this week that 90 per cent of tests were turned around within 48 hours. He said the majority at mobile and drive-through centres were completed within 24 hours. He committed “to get all tests turned around in 24 hours by the end of June, except for difficulties with postal tests or insuperable problems like that”.
A Department of Health spokesman said: “We have already made huge improvements in turnaround times with the majority of people who get in-person tests receiving their results in less than 24 hours. This will further improve in the coming weeks.”