This double-blind, randomised study was performed to assess the immunogenicity and reactogenicity of three lots of a quadrivalent
diphtheria-
tetanus-acellular
pertussis-
hepatitis B vaccine (
DTPa-HBV) co-administered with three lots of Haemophilus influenzae type b conjugate (Hib) vaccine in one injection, as a primary vaccination course in healthy infants at 2, 4 and 6 months of age. 269 infants (8-11 weeks of age) were randomly allocated to three groups to receive
DTPa-HBV/Hib
vaccines, concomitantly with oral
polio vaccine. Blood samples for antibody determinations were taken before vaccination and 1 month after the third dose in 262 subjects. Local and general symptoms were recorded by parents on diary cards. All vaccinees had post-vaccination protective
anti-D and
anti-T (> or = 0.1 IU ml-1)
antibodies, and 98% had protective anti-HBs antibody titres (> or = 10 mIU ml-1). There were no statistically significant differences between groups in post-vaccination
anti-D,
anti-T, anti-HBs antibody geometric mean titres (GMT), these being 3.49 IU ml-1, 5.92 IU ml-1 and 1109 mIU ml-1, respectively. All subjects responded to three
pertussis components, i.e.
pertussis toxin (PT), filamentous haemagglutinin (FHA) and
pertactin (PRN). Although statistically significant differences in GMTs of anti-PT, anti-FHA and anti-PRN were found between groups, these were not believed to be of any clinical relevance as the minimum GMTs were 60, 193 and 230 EL.U ml-1 for anti-PT, anti-FHA and anti-PRN, respectively. There were no statistically significant differences in anti-PRP antibody GMT (4.05 micrograms ml-1) between groups, 100% and 85% of subjects having titres > or = 0.15 and 1.0 microgram ml-1, respectively. No symptoms were reported for one third of the subjects.
Fever (> 38 degrees C) was reported after 16% of doses, with < 1% having > 39.5 degrees C. Almost all local and general symptoms were mild or moderate, and lasted less than 48 h. No subject dropped out due to a severe adverse reaction. The administration of an experimental mix of
DTPa-HBV and Hib
vaccines in a single injection is safe, well-tolerated and immunogenic for all
vaccine components.