Northamptonshire's Test and Trace teams are reaching nine out of ten targets in the battle to slow the spread of Covid-19.
The county squad, which took over following up positive tests last summer, is now among the top in the country with a 90 per cent hit rate — despite huge rises in numbers of cases since Christmas.
Around 5,500 positive tests a week were being reported in Northamptonshire in early January.
But the team have increased the numbers being tracked down from around 70 per cent when the scheme was launched nationally.
County Council Director of Public Health, Lucy Wightman, said: "There is still a little room for improvement and obviously we'd like to reach 100 per cent but overall we're managing to get to a much higher proportion of cases.
"People are getting the information they need that they are at risk and receiving advice on what support they might need while they self-isolate."
A further 82 per cent of contacts of those testing positive are also being identified.
Mrs Wightman told Thursday's county council Oversight and Engagement Board meeting: "This a really good achievement and thanks to the teams that even with the number of cases we've seen a significant increase and case-load over the last few weeks, they've been able to follow up that high number of people."
The NHS Test and Trace system was launched to ensure that anyone with Covid-19 symptoms can quickly be tested to find out if they have the virus.
With the help of mobile apps, teams them trace close recent contacts of anyone who tests positive and, if necessary, notifies them they must self-isolate for ten days at home to avoid the risk of them spreading of the virus.
But it came under fire from critics for failing to hit targets and letting too many slip through the net after testing positive.
County Council cabinet member, Ian Morris, said: "The fact that we are reaching 90 per cent in Northamptonshire now is good news and it is a remarkable improvement from when it was a national system.
"Testing and contact tracing is going to be very important going forward, and we have formed a very good basis there for our testing whatever form that might take."