Corby's seven-day rate of positive Covid-19 cases is the second highest in the country, new figures have revealed.
The borough's rate is now 521 per 100,000 people - topped only by Sandwell in the West Midlands at 523.
Corby's rate is steadily falling week-on-week, having been 611 a week ago, but is not dropping at the same speed as other local authorities.
Yesterday's case numbers saw the borough rate per 100,000 increase by 50 after 41 positive cases were added, taking the total number of cases to 4,153.
It was the biggest daily rate increase in England, with Kettering coming in at number two after increasing from 330 per 100,000 people to 361 with another 48 positive cases.
However Corby's current high seven-day rate may be partly due to the lateral flow test centre which opened at Lodge Park Sports Centre last month.
Public health bosses hope it will reduce the asymptomatic spread of the virus by offering quick, regular testing of those who do not have Covid-19 symptoms to identify those who may be infectious without knowing it.
There have been suggestions that the high number of people working in manufacturing and logistics might be vulnerable and these groups, among several others, have been prioritised for tests.
Corby's centre has been working at 100 per cent capacity and last week we reported how it was to be extended to test 500 people every day.Those who test positive in a lateral flow test then take a PCR test for confirmation that they have Covid-19.
The number of people who have tested positive at Corby's lateral flow test centre and then tested positive in a PCR test is not known, but the borough's current rate is likely to include some asymptomatic workers who may not have had a positive test recorded had the lateral flow test centre not opened.
Speaking at a press conference last week, Corby Council leader said it was comforting to see a 'slight' reduction in Corby's Covid levels.
But he said it was not a reason to be complacent and urged people to follow the rules.
He said: "There are serious issues still facing us and it's important we continue to observe the guidance."
Three other areas of Northamptonshire are currently inside the top 50 seven-day Covid case rates in England.
Northampton is number 19 with 397 cases per 100,000 people.
Wellingborough and Kettering are numbers 34 and 35, with case rates of 363 and 361 respectively.
East Northamptonshire is number 150 with a case rate of 250.
Official figures on the Government website, which show Corby as having the fifth highest seven-day rate in the country, are five days behind.