Targeted Covid-19 testing is taking place across two secondary schools in Dartford to identify potential cases of the Delta variant.
Students at Wilmington Grammar School for Girls and Wilmington Grammar School for Boys are being asked to visit a mobile van to take a PCR test this week.
Endeavour MAT, the Trust responsible for both schools, is working with Public Health England and Kent County Council to coordinate efforts.
The Trust says it is assisting "as a precaution" and that all results will be used to determine whether the variant has spread more widely.
Endeavour chief executive Donna Lodge said: “The health, safety and well-being of our whole school community is of paramount importance and throughout the pandemic we have always followed the latest Government guidance to keep our students and staff, and their families, safe and well; we continue to do so now.
"Social distancing will be in place during the testing and appropriate hygiene guidance will be followed."
She added: "Staff will ensure testing is carried out with minimal disruption to learning.
"Students, parents or carers who have any concerns are always welcome to speak to a member of staff.”
Since pupils returned to in-class teaching on March 8, the government has advised all secondary students and teachers to test at home using lateral flow kits.
But cases of the Delta variant, first detected in India, are rapidly on the rise in schools across the country and have now overtaken the Kent variant, according to the British Medical Journal.
Latest figures show potential cases in Kent are on the rise.
To track the variant faster, scientists are testing positive samples for something known as an S-gene, which is present in the Indian strain but not the Kent one.