Researchers from UCL and the London School of Hygiene and Tropical Medicine used computer models to see how the virus might spread in the UK as pupils returned to the classroom and their parents were more able to go back to work or resume other activities.
The study assumes children are less likely to catch - and therefore spread - coronavirus and that some parents would continue to work from home.
As first reported in June, the combined effect on pupils and parents would be enough to cause a second wave if there was no effective test-and-trace programme.
This would happen around December 2020 and would be twice as big as the first peak, unless the government took other actions such as reimposing lockdown.
The study, now formally published in the Lancet Child and Adolescent Health, shows a second wave could be prevented if:
- both 75% of people with Covid symptoms were found and 68% of their contacts traced or
- both 87% of people with symptoms were found and 40% of their contacts traced