New Test and Trace data shows that from September 2 to September 8, there were 934 new Covid-19 cases recorded in Peterborough.
Of these, 225 (24%) were in people over 10 and in their teens.
A further 113 cases were found in those under the age of 10, meaning more than a third (36%) of cases were found in residents younger than 20.
The 10-19 age group had the highest proportion of new cases in the seven days to September 8.
The second most affected group was people in their 30s, who made up 15% of all new cases.
No people over the age of 90 tested positive, after six were diagnosed in the week to September 1.
In the week to September 8, a total of 8,994 coronavirus tests were conducted in Peterborough, with around 10% of these returning positive results.
But slightly more recent data shows that cases are falling in the city, with 803 people testing positive in the seven days to September 11. The current rolling case rate is 396.3 per 100,000 people.
Children over the age of 12 will be eligible for the Covid-19 vaccine from next week, it was announced on September 14.
The decision to go ahead comes despite the JCVI deciding not to recommend mass vaccination of 12 to 15-year-olds.
The experts had said Covid-19 presents a very low risk for healthy children and that vaccination would only offer a marginal benefit.
But they suggested that wider issues, such as education, should be taken into consideration and examined by chief medical officers (CMOs) of each of the four UK nations.
Professor Anthony Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation (JCVI), told the Today programme: “What we tried to do right the way through the pandemic as a committee is to be open and honest with the public and give them the best advice possible… I think the public in the end will appreciate our honesty and I think they will also appreciate the CMOs’ perspective and the government offering them choice.
“I agree it will cause uncertainty, hesitation and debate within families, but sometimes life isn’t black and white, and this is one of those situations.”