England will return to a regional approach from 2 December but the tiers will be "tougher", the PM says.
The Swale district of Kent now has the second highest coronavirus infection rate in England.
For Christmas break, students will leave university within 24 hours of two negative Covid tests.
Up to 4,000 fans will be allowed at outdoor events in the lowest-risk areas when the four-week national lockdown in England ends.
The vaccine is cheaper than other options and easier to distribute around the world.