What do you give to a child younger than 1 year of age if they were exposed to the chickenpox or zoster virus?

The minimum age for varicella vaccine is 12 months. Vaccination is not recommended for infants younger than 12 months of age even as post-exposure prophylaxis. CDC recommends that a healthy infant should receive no specific treatment or vaccination after exposure to VZV. Treatment with antiviral medication may be considered if the infant is at increased risk of moderate to severe varicella infection.

See the Varicella Zoster Immune Globulin section for details on the recommended use of VariZIG in immunocompromised children, infants exposed to varicella around the time of birth and some hospitalized preterm infants.