Hundreds of contacts not reached through Test & Trace in Bucks
35% of people identified in Buckinghamshire couldn't be contacted.
Fewer than two-thirds of close contacts of people with coronavirus in Buckinghamshire are being reached through the test and trace regime, figures suggest.
The Government has faced mounting pressure over failings in the NHS Test and Trace system, which has recently seen up to four times the number of people trying to book a test as the number of tests available.
It comes amid rapidly rising case numbers, which could result in 50,000 new cases every day by mid-October unless the current rate of infection is curbed, according to the Government's chief scientific advisor.
Data from the Department for Health and Social care shows 601 people who tested positive for Covid-19 in Buckinghamshire were transferred to the Test and Trace service between May 28 and September 9.
Coronavirus patients reached by the service are urged to give details for anyone they were in close contact with in the 48 hours before their symptoms started, the NHS says.
A further 1,596 close contacts were identified in this way in Buckinghamshire – also referred to as "non-complex" cases, meaning they could be dealt with through a call centre or online.
But the figures reveal just 65% of those were reached by contact tracers over the period, meaning 565 people did not acknowledge they also needed to self-isolate.
The DHSC says a close contact is not reached when there is no response to text, email or call reminders, or when their communication details were not available.
Across England 64% of non-complex close contacts were reached and told to self-isolate by NHS Test and Trace in the latest week to September 9.
Saffron Cordery, chief executive of NHS Providers, said this falls "well short" of SAGE's 80% target.
She said:
“Trust leaders are increasingly concerned with the current testing shortages impacting on NHS service recovery and winter preparations due to staff and their family members being unable to access a test.
“Additionally, with the number of positive Covid-19 cases increasing, but a reduction in the proportion being contact traced, we are looking at renewed pressure on the NHS."
Baroness Dido Harding, who heads up the NHS Test and Trace service, admitted last week that demand for tests was outstripping capacity but denied claims that the system was "failing".
She suggested around a quarter of those coming forward for a test did not have symptoms.
Under new rules, from September 28 people in England will legally have to self-isolate for 14 days if they test positive for coronavirus, or they are instructed to do by NHS Test and Trace.
Fines for non-compliance will start at ÂŁ1,000, rising to ÂŁ10,000 for repeat offenders, while people on benefits will be eligible for a one-off support payment of ÂŁ500 if they face a loss of earnings as a result of having to quarantine.