Details of reduced Arriva and Go North East services can be found here:
https://www.arrivabus.co.uk/coronavirus/important-service-information—north-east/
https://www.gonortheast.co.uk/
Changes start this weekend 28/29th March. Most services will reduce to 1 an hour whilst some main routes will still run every 30 minutes.
So the 64 and 21 services will run every half hour.
The 62, 14 and X21 will run hourly.