Fines of £800 will be handed to anyone attending a house party of more than 15 people from next week.
Boris Johnson says England's measures will be reviewed once the priority groups have had the vaccine.
Severe flood warnings remain in place in England and Wales, as further rain is expected next week.
The education secretary says schools in England will be given two weeks' notice before reopening.
The Worthy Farm event has been scrapped for a second year running due to the global pandemic.