UP to 20,000 kids and teachers will be swabbed for Covid to check whether the virus spreads within schools.
Matt Hancock wants tests to be carried out at 100 educational settings – including 15 in London – before the summer holidays.
The Health Secretary says the crucial data will help us better understand rates of transmission within schools.
Experts will also be able to accurately estimate how many children carry the bug but have no symptoms of the disease.
Nurses will carry out regular swabs on 200 teachers and pupils from each setting to look for infections.
And medical professionals will also take a blood test at the start and end of the study in 40 schools, to see if participants have antibodies against the bug.
Officials hope the findings will help open up classrooms to more children in September by revealing how to best minimise coronavirus spread.
Mr Hancock said: “A critical pillar of our Covid-19 testing strategy is surveillance – testing samples of the population to gain a deeper understanding of the spread of Covid-19 – especially in those who may not have symptoms.
“This study will help us better understand how common asymptomatic and mild cases of Covid-19 are so that we can support parents, pupils and teachers and staff, and inform our ongoing response to this new virus.”
Volunteers will need both headteacher and parent permission before taking part, with nurses visiting schools to carry out checks.
Some participants will also give a two blood samples to look for antibodies against the virus, which show they previously have had the bug.
They will all have five weekly swabs to test whether they currently have the infection.
The pilot scheme, run by Public Health England, will inform a much bigger school surveillance study in the autumn.
Education Secretary Gavin Williamson said: “We know that being in school is vital for children’s education and their wellbeing.
“Last week, primary schools began to welcome back some pupils and secondary schools will begin to do the same from 15 June, as part of our phased and cautious approach to getting children and young people back into the classroom.
“Studies like this will be invaluable as we continue moving forward with those plans, and help us assess the next steps for getting all children back into schools, nurseries and colleges with their friends and teachers.”
Britain’s top child doctor welcomed the research, saying it will help reassure parents and teachers.
‘SAFE FOR SCHOOLS TO REOPEN’
Professor Russell Viner, President of the Royal College of Paediatrics and Child Health, said: “This is a really important step. We need to clearly understand what role children and schools plan in transmission of the virus.
“More data collection is crucial to reassure people that it is safe for schools to reopen and carefully monitor their impact on Covid spread.
“This will tell us how rapidly we can get children back into school.”
Community surveillance by the Office for National Statistics has already found the number of infected people in England has halved in two weeks.
Officials say there were an estimated 39,000 new infections per week, or 5,600 a day, from April 26 to May 30.
Speaking at the Downing Street briefing, Mr Hancock announced an extension of Covid testing in English care homes.
He said working age adult care homes would now be included.
Ministers have already sent testing kits for all residents and staff in elderly care settings by their early June target date.
Mr Hancock said: “We will now make sure that we do all of this in working age care homes as well.
“I can announce that from today all remaining adult care homes in England will be able to order the whole care home testing service for residents and staff.
“This service will benefit residents and staff in over 6,000 more care homes.”