Background:Confidence in hexavalent vaccines has recently been shattered in Germany, after 5 infant deaths occurred shortly after such a vaccination. The aim of this study was to evaluate the safety of hexavalent vaccines over a time period of 2 years.Material/Methods: With the written informed consent of the parents, we enrolled in the study all healthy infants who attended our office for a primary scheduled infant immunization during the study period from July 1, 2001, to June 30, 2003. This period was divided into two parts: (1) In a pilot study (July 1 to December 31, 2001), the two hexavalent vaccines licensed in Germany, Hexavac[sup]®[/sup] and Infanrix hexa[sup]®[/sup], were compared to each other to evaluate if one of these vac­cines would be better tolerated. (2) During the follow-up study period (January 1, 2002, to June 30, 2003), that hexavalent vaccine was to be used, if any, which had been shown to have lower side effects during the pilot period. The trivalent measles-mumps-rubella vaccine Priorix[sup]®[/sup] was applied to all infants during both study periods. The parents were advised to im­mediately consult our office in any case of suspected or proven side effect from the vaccination.Results: 3658 polyvalent (hexavalent and trivalent) vaccinations were applied to 1997 infants. Local reactions were observed after application of Priorix[sup]®[/sup] in 0.0%, of Infanrix hexa[sup]®[/sup]. in 0.46%, and of Hexavac[sup]®[/sup] in 3.1%, respectively.Conclusions: The safety of Priorix[sup]®[/sup] and Infanrix hexa[sup]®[/sup] in particular could be established. Hexavalent vaccines can be recommended for introduction in all European countries for primary scheduled infant immunizations.

Keywords: Vaccines, Combined - adverse effects, Vaccines, Combined - chemistry, Vaccines, Combined - immunology, Vaccines, Combined - therapeutic use, Germany, Pilot Projects, Vaccines, Combined - therapeutic use