Current testing and tracing are said to be insufficient to stop a second wave of coronavirus after schools within the UK reopen, scientists have warned.
The increased transmission would also result from parents not having to remain reception with their children, they say.
Researchers said getting pupils back to high school was important – but more work was needed to stay the virus in restraint.
The UK government said plans were in action to make sure schools can reopen safely at the beginning of the varsity year.
England, Wales, Scotland and Northern Ireland have separate contact tracing systems.
Asked about the estimate that only 50% of contacts are being traced in England, Simon Clarke, minister for regional growth, told the BBC government figures were higher.
He said NHS test and trace is “maturing all the time” and getting children back to high school within the autumn may be a “top priority” that the govt wouldn’t “be willing to trade”.