What happens to unused vaccine doses?

Once a vial of vaccine is opened, it must be used within a certain amount of time. What happens to unused doses depends on who is giving the shots.

Deal offers California school districts money to reopen classrooms

Under the deal announced Monday, school districts could receive up to $6.6 billion if they reopen classrooms by March 31. The proposal does not require staff and students to be vaccinated, and districts are not required to have agreements with teachers' unions.