Safety and immunogenicity of administering all childhood vaccines for children 12-15 months of age at a single visit

An increasing number of vaccines must be administered to young children, requiring additional visits and healthcare costs. To evaluate the safety and imunogenicity of administering DTP or DTaP, MMR, V, and Hib vaccines to children 12-15 months of age at a single visit, 350 toddlers were randomized to 4 grps: Vaccine, Bloods by Time Post 1^st Immunization (12-15 mos of age) Grp Vaccination 6 wks post 12, wks 1 yr 1 MMR, V, DTP-Hib (Bld) (Bld) (Bld) 2 MMR, V, DTaP, Hib (Bld) (Bld) (Bld) 3 MMR, V (Bld) DTP-Hib (Bld) (Bld) (Bld) 4 MMR, V (Bld) DTaP, Hib (Bld) (Bld) (Bld) Reaction rates were not diff between the grps that received all vaccines at a single visit or at 2 visits. Those who received DTP had significantly more reactions than those who received DTaP. Reaction rates by type and by study grp varied between 2% and 25% in the 24 hours post-immunization, but then subsided. Increased reactions were noted between 9 and 12 days following immunization. The following serologies were performed: ELISA to D, T, PT, FHA, Hib, ME, MU, R, and V. There were no significant differences in antibody levels for any of the antigens between subjects that received all vaccines in a single visit versus those at 2 visits. Antibody levels wane between 6 weeks and 12 months for Hib, D, T, PT and FHA, but not for ME, MU, R, or V. Antibody levels to PT and FHA were signficantly higher in the 2 grps that received DTaP compared with the 2 grps that received DTP. We conclude that the 4 childhood vaccines recommended for toddlers can be administered at a single visit without adverse consequence.