Thirty six Lincolnshire schools reported 61 positive test results in the seven days leading up to Friday, March 26, according to Lincolnshire County Council.
The county council said that between March 12 and 18, 71,146 later flow tests were carried out via schools, of which 85 were positive.
In February, the amount of tests carried out using lateral flow and asymptomatic tests in Lincolnshire every week was around 5,000 to 6,000 for all ages.
When children started doing tests and secondary school staff did them twice weekly it went up to 70,000 tests a week.
Over the last few weeks, over 70,000 asymptomatic tests per week have been carried out, with only one person in every 1,000 coming back positive.
Andy Fox, consultant in public health for the county council, said it was a mixed picture as “we’re seeing the numbers go up because we’re doing so much more testing in those age groups than we’ve ever done before”.
He said they are finding very little COVID-19 in secondary school pupils compared to the amount of COVID they expect to find in the same working age level.
The rates of COVID and the prevalence of it in those groups is “pretty low”, he said.
Mr Fox added: “Schools continue to take measures to limit the potential spread of the virus and will inform parents of positive cases where necessary.
“However, in some cases, the person testing positive may have already been out of school, meaning there is no impact on other pupils or staff.
“It’s also important to remember that, due to the expansion of testing at home for staff, pupils and parents, positive cases may not be the result of transmission within school.”