Covid-19 has been identified in 0.5pc of people since surge testing for a variant of the disease began in Diss and Roydon.
Mass testing in part of south Norfolk comes to an end on Wednesday - two weeks after the virus strain first found in South Africa was detected in a handful of cases.
So far, around 60pc of people who live in the town and neighbouring village have been tested, which is more than 6,000 people.
It means about 30 people have registered positive results for coronavirus at testing stations, or after using home testing kits.
The rate of infection in Diss and Roydon therefore stands at around 500 cases per 100,000 people, compared to 54 per 100,000 in the overall district of South Norfolk.
Crucially, health officials say it is too early to confirm whether any of the subjects who tested positive are carrying the South African variant.
Results are currently being sequenced and more information will become available in the coming days.
Surge testing was launched in Diss and Roydon in mid-February, in an attempt to ascertain whether the virus strain had spread across the community.
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Letters were sent to 10,000 people and Dr Louise Smith, director of public health for Norfolk, said testing as many as half would be a positive outcome.
As of last Wednesday (February 24) - just five days after efforts got under way - around 6,100 people had participated in the targeted approach.
More than 2,600 had been tested at three mobile units, while around 3,500 home testing swabs had been returned out of 4,000 issued.
Norfolk Public Health and South Norfolk Council have since continued to urge those who have not yet returned or booked a test to do so.
Anyone who tests positive is being told to self-isolate immediately with their households and pass on details of their contacts to NHS Test and Trace.
At the beginning of February, experts said cases caused by the South Africa variant were being "watched like hawks" in Norfolk.
There is no evidence that it causes more serious illness for the vast majority of people who become infected, but there are concerns it may spread more easily.
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