The Advisory Committee on Immunization Practices (ACIP) recommends a two-dose vaccine schedule for measles, mumps, rubella and varicella vaccines for children, with the first dose at age 12-15 months and the second at age 4-6 years.he Advisory Committee on Immunization Practices (ACIP) recommends a two-dose vaccine schedule for measles, mumps, rubella and varicella vaccines for children, with the first dose at age 12-15 months and the second at age 4-6 years.