Apr 2, - MMR is contraindicated during pregnancy and in severe immunodeficiency. 4. Varicella vaccination. • All adults without evidence of immunity to. Nov 22, - CDC recommends two doses of chickenpox vaccine for children, adolescents, and adults. Children should receive two doses of the vaccine—the first dose at 12 through 15 months old and a second dose at 4 through 6 years old.