Responses of Premature Infants to Measles-Mumps-Rubella (MMR) and Varicella Vaccines

The purpose of this study is to see if the MMR and chickenpox vaccines work as well in premature infants as in children that were carried to full term. A group of children who were carried full-term will be matched for age, sex, and race and will be used for comparison. Extremely premature infants (born at <28-30 weeks gestation) have lower antibody responses than full-term infants to several vaccines given at the postnatal ages recommended for full term infants. We propose to evaluate the immunogenicity of varicella and mumps-measles-rubella (MMR) vaccines in relatively healthy 15 month-old children born at <29 weeks gestation. This is a phase IV, observational study with 2 study arms having 16 infants each. The first group will enroll infants 9-12 months old that were born premature (<29 weeks gestation). The second group will be matched for sex, race, and postnatal age, but will have been full term (>= 37 weeks gestation) at birth. Infants will be vaccinated at visit 1 and post-vaccine serology will drawn at visit 2 (4 to 6 weeks after visit 1).