Wash your hands thoroughly with soap and water
especially after using the toilet or changing diapers
always before eating, preparing, or handling food, and
before giving yourself or someone else medicine.
Norovirus can be found in your vomit or poop even before you start feeling sick. The virus can stay in your poop for 2 weeks or more after you feel better. It is important to continue washing your hands often during this time.
You can use alcohol-based hand sanitizers in addition to hand washing.
But, you should not use hand sanitizer as a substitute for washing your hands with soap and water. Hand sanitizers aren’t as effective as washing hands with soap and water at removing norovirus particles.
link to source: https://www.cdc.gov/norovirus/about/prevention.html