These are the 13 neighbourhoods in and around Northampton, Kettering, Wellingborough and Corby with weekly Covid-19 case rates among the highest in the country.
Protection from vaccines is keeping the number of hospital cases and deaths lower than during the second wave of the pandemic earlier this year.
But experts are concerned the virus is still being spread at the same time as flu season is fast approaching.
Weekly rates in parts of Kettering, and clusters of villages near Wellingborough and Northampton are now over 1,000 per 100,000 people — around three times the UK average.
County Public Health director Lucy Wightman said: "People who say they just want to catch Covid and get it out of the way don't understand that you can catch it again.
"This isn't like chicken pox where you typically have it once in your lifetime. This is a virus that is mutating and even smallest mutations mean you can be infected again within a matter of weeks of overcoming a first infection.
"We're highly likely to see flu cases go up during the autumn and winter because everything is back open and you can be infected with both things at once.
"If you get both flu and Covid at the same time you are four times more likely to die."
Northamptonshire's two main NHS hospitals were treating 92 Covid patients according to latest figures issued Thursday (October 7) following an influx of more than 17 in four days at Northampton General Hospital.
Just under half the 21 patients in the hospitals' critical care beds have Covid.
Mrs Wightman added: "Covid-19 is a very infectious respiratory disease and can be easily transmitted to older, more vulnerable people.
"Everybody knows the drill that the basics really work — testing, getting vaccinated, giving people space, wearing face coverings and hand washing.