Data from the Department for Health and Social care shows 4,541 people who tested positive for Covid-19 in the area were transferred to the Test and Trace service between May 28 and November 4 – with 721 being diagnosed in the final week of that time period.
This led to 10,376 close contacts being identified – but just 63% were reached in the week-ending November 4 – the seventh consecutive week that the success rate for Test and Trace has fallen.
In England, only 59% of contacts were reached and told to self-isolate by the NHS Test and Trace system in the week to November 4.
NHS Providers say that the test and trace system has a long way to go to be effective.
Saffron Cordery, deputy chief executive of NHS Providers, which represents NHS trust leaders, said: "The number of people who tested positive for COVID this week has increased by 8%.
"Despite this, it is worrying to see fewer close contacts identified than the previous week, and with over 124,000 not reached this week it highlights how far the system has to go to be effective.”
She added: "We remain hopeful that the number of people testing positive for COVID will reduce as national lockdown continues.
"We are however realistic about the fact that this winter is going to be extremely challenging, particularly so without a world class testing and contact tracing system."