Fever as a marker of reactogenicity of an acellular pertussis-containing hexavalent vaccine (HEXAVAC) in a large-scale, open, randomized safety study in healthy French infants.

Objective: New multivalent vaccines simplify childhood immunisation schedules and can increase vaccination coverage. However, they must have a reactogenicity profile which is acceptable and comparable with that of previously available vaccines. The objective of this trial was to assess the incidence of fever of 40.0 degrees C or higher following vaccination with HEXAVAC or concomitant PENTACOQ and HBVAXPRO.

Study Design: This was an open, randomized, pragmatic, post-licensure multicenter trial performed in France. Infants were randomly assigned to receive either a single injection of a hexavalent, aP-containing vaccine (HEXAVAC) or separate injections of a pentavalent, wP-containing vaccine (PENTACOQ) and Hepatitis B vaccine (HBVAXPRO) at 2, 3 and 4 months of age. Both groups received a HEXAVAC booster at 12-18 months of age.

Results And Discussion: 7151 infants were enrolled in 389 centers. During the combined three-day periods following the primary series injections, the incidence of fever of 40.0 degrees C or higher with HEXAVAC was not greater than with [PENTACOQ and HBVAXPRO]. The incidence of fever at thresholds of 38.0 degrees C, 38.5 degrees C, 39.0 degrees C and 39.5 degrees C was significantly lower in the HEXAVAC group. The vaccine attributable risk for fever of 40.0 degrees C following the booster injection with HEXAVAC was statistically acceptable.

Conclusion: The incidence of fever of 40.0 degrees C or higher in this study was very low and similar in both groups (HEXAVAC or [PENTACOQ + HBVAXPRO] as a three-dose primary series). Fever > or =38.0 degrees C and < or =39.5 degrees C was significantly less frequent following administration of HEXAVAC. The incidence of fever of 40.0 degrees C or higher following a HEXAVAC booster dose was low in all infants studied.