In total, 7,941 people were referred for contact tracing in the week to 19 August. Of those, 6,115 people tested positive that week, a drop of 8 per cent, while 1,826 people who were known to have tested positive in the previous week were not referred because of the technical problem.
England’s test and trace service has been hit by technical issues that delayed contact tracing for almost 2,000 people infected with the coronavirus.
An internet outage was blamed for the delays in people being referred to contract tracers, with the service consequently unable to reach any of the close contacts of the infected people.
On Thursday, the UK reported the highest numbers of positive coronavirus tests since 12 June, with 1,522 confirmed infections. In the previous 24 hours, 12 people died within 28 days of a positive infection result, bringing the UK death toll to 41,477.
A weekly performance report said of the number of people referred for contact tracing: “This is an increase of 65 per cent compared to the previous week. This is partially due to a temporary infrastructure issue which resulted in a delay between some people testing positive and being transferred to NHS Test and Trace.”
The Department of Health and Social Care said the internet outage occurred in the Southampton area earlier this month and prevented the details of infected people being electronically passed to the test and trace system.
There was also a significant rise in the turnaround time for test results in the week to 19 August.
The numbers of test results received within 24 hours from Covid-19 testing centres dropped 20 per cent to just over 40 per cent, meaning a majority of people were waiting longer than a day to get the results.
The median time for a test result being received by a patient after being swabbed at a regional test centre was 27 hours in the week to 19 August, up from 23 hours the week before. For mobile testing, the wait was 25 hours, up from 21 the week before.
For home-testing kits, the median turnaround time is 71 hours.
The prime minister, Boris Johnson, promised that tests would be delivered in under 24 hours by the end of June.
Time is crucial for contact tracing to work because the aim is to reach those who have been in close contact with infected people and who may be infected themselves but do not yet have symptoms, unknowingly spreading the virus to others as a result.
In the week to 19 August, only 75 per cent of close contacts of people infected with the virus in England were reached. It is the ninth week in a row in which the government’s Scientific Advisory Group for Emergencies (Sage) target of isolating 80 per cent of contacts within 48-72 hours has been missed.
Since the launch of test and trace, 65,398 people who tested positive for Covid-19 in England have been referred for tracing.
A total of 50,876 people, 78 per cent, were reached and asked to provide details of their contacts, while 12,851 people could not be contacted.
Local health-protection teams continue to perform better in reaching contacts and asking them to self-isolate than cases handled online or by call-centre staff.
For cases handled by local teams, 96 per cent of contacts were reached and asked to self-isolate in the week to 19 August.
By contrast, for those cases handled either online or by call centres, 62 per cent of close contacts were reached.
Since the launch of test and trace, 246,262 close contacts of people who have tested positive for Covid-19 have now been reached through the system and asked to self-isolate.
This is 81 per cent of a total of 305,725 people identified as close contacts.
Saffron Cordery, deputy chief executive of NHS Providers, which represents NHS hospitals, said the results were a “mixed picture”.
She said:s “
“It’s also good that more people are being transferred to the contact tracing system – in large part because a glitch in the system has now been fixed.
“But it’s worrying to see that too many people are still not being reached by the system.
“It’s also a real concern that overall turnaround times for swabs taken in the community are taking longer. This is a key component of an effective test-and-trace system which we’ll need for the months ahead. Clearly, we’re not there yet.”
A spokesperson for the Department of Health and Social Care said: “Following a major internet outage in mid-August in the Southampton area, we are aware that a number of positive cases were not transferred to NHS Test and Trace in the usual way.
“This did not affect the delivery of test results and all those testing positive during this period were advised to self-isolate.
“All cases affected were transferred to the system for contact tracing as soon as this issue was resolved.”