An open, randomised, multicentre trial was performed to compare the reactogenicity
and safety profile of the administration of a hexavalent diphtheria-tetanus-acellular
pertussis-hepatitis B-inactivated polio (DTPa-HBV-IPV) vaccine administered in one
injection mixed with Haemophilus influenzae type b (Hib) conjugate vaccine (Group
1) with that of a pentavalent DTPa-IPV vaccine mixed with a Hib vaccine (DTPa-IPV/Hib),
simultaneously administered with HBV (Group 2) in two injections in opposite thighs,
as a primary vaccination course, to healthy infants at 2, 4 and 6 months of age. A
total of 235 completed the study, 120 from Group 1 and 115 from Group 2. Blood samples
(pre-vaccination and 1 month after the third dose) were obtained from a subset of
infants (Group 1: 40; Group 2: 31) to assess the immune response to vaccination. Local
and general solicited symptoms were recorded by parents on diary cards. Seven hundred
and five diary cards (Group 1: 360; Group 2: 345) were collected. The clinically relevant
and most commonly reported local reaction was pain (infant cried when the limb was
moved) in 2.5% (Group 1) and 1.2% (Group 2) of diary cards. Fever was more frequently
reported in Group 1 (21% of diary cards) than in Group 2 (12% of diary cards). However
only 3 and 2% of doses in Groups 1 and 2, respectively, were responsible for a rectal
temperature between 38.6 and 39.5 degrees C and only one case (Group 2) had > or =39.5
degrees C. Other clinically relevant general symptoms were rarely recorded: irritability
(2-2.8%), loss of appetite (0.3-0.6%) and drowsiness (0.3-0.3%). All subjects included
in the immunogenicity analysis had seroprotective titres to diphtheria, tetanus, polio
virus types 1 and 3, Hib. Almost all subjects were seroprotected for anti-polio type
2 and hepatitis B (with the exception of 1 subject in Group 1 for each antigen). The
vaccines response rates to pertussis antigens were over 97 and 90% in Groups 1 and
2, respectively. This study shows that, from a clinical perspective, the DTPa-HBV-IPV/Hib
vaccine given in a single injection has a similar reactogenicity and safety profile
to that of two licensed vaccines (DTPa-IPV/Hib, HBV) given in two simultaneous injections
to infants at 2, 4 and 6 months of age. This is a valuable advantage, since in some
countries, such as Spain and the UK, an additional injection (for the administration
of meningococcal C conjugate vaccine) has been recently included in the infants' vaccination
calendars.