Secondary school pupils in an area with one of the highest coronavirus rates in England have been asked to get tested for coronavirus even if they are not showing symptoms.
Basildon had the ninth-highest rate in England with 314 cases per 100,000 people in the week to 29 November.
Essex County Council is introducing the "targeted approach" at The Bromfords School and Basildon Lower Academy.
It said 24.6% of cases in the district were were in the 10-19 age group.
Tests were available to the end of term.
The council said it had written to parents and carers at the two schools, but it will be also be contacting others which have "a confirmed outbreak or an increasing number of cases in the school community".
Testing will "avoid blanket closures and any impact on schools in areas with lower infection levels".
The "appropriate and proportionate measures" will prevent further spread, without disrupting education, the council added.
Anyone who tested positive, but were asymptomatic could be instructed to self-isolate.
Dr Mike Gogarty, the council's director of public health and wellbeing, said: "Encouraging parents and carers to book tests for their child if they attend one of the identified schools will help us to act more quickly and reduce the likelihood of cases spreading even further.
"It is also part of wider work being undertaken across all schools in the district to reduce the rate of transmission, including a review of the threshold criteria for year groups and bubbles to self-isolate so that schools can take action on the basis of smaller numbers of cases."
He added that it was "vital" everyone adhered to government guidelines, by socially distancing at all time, in and outside of school.
Basildon coronavirus statistics:
- 253 coronavirus-related deaths registered up to 20 November
- 314 cases per 100,000 people for the week 23-29 November
- 588 cases in the week 23-29 November
- 3,995 cases in total during the pandemic, up until 3 December
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