Schools in England may need to have staggered start times for different groups when they reopen to all pupils in September.
The government has today released guidance on how schools should ensure they are safe when they fully reopen in the autumn.
The guidance from the Department of Education outlines how schools should limit contact between different groups of people to minimise the risk of spreading coronavirus.
"Schools must do everything possible to minimise contacts and mixing while delivering a broad and balanced curriculum," the guidance states.
It has been suggested that pupils should be put into groups or bubbles, depending on who they have lessons with.
These could be whole year groups in secondary schools or separate classes in primary schools.
The guidance says these groups should be kept apart, which means large gatherings such as assemblies or collective worship with more than one group should not go ahead.
It also suggests that groups should be kept apart when arriving and leaving school.
That means that schools may have to implement staggered start and finish times for different groups.
"Schools should consider staggered starts or adjusting start and finish times to keep groups apart as they arrive and leave school," the guidance states.
It says staggered timings should not affect the overall amount of teaching time.
It adds: "While passing briefly in the corridor or playground is low risk, schools should avoid creating busy corridors, entrances and exits.
"Schools should also consider staggered break times and lunch times (and time for cleaning surfaces in the dining hall between groups)."
