HBV and Hib and MenC conjugate vaccines are immunogenic in infants but repeated injections are required to elicit long-term immunity. Also, when these vaccines are formulated into a combination vaccine, responses to individual antigens may be suboptimal. Chiron Vaccines has developed a proprietary microfluidized oil-in-water emulsion adjuvant, designated MF59. MF59 has been extensively investigated in humans (N >7,000), and has been found to be very safe and to enhance immune responses to recombinant viral glycoprotein vaccines in infants and toddlers. To investigate the potential of MF59 for formulation of combination vaccines intended for infants, infant baboons (N=6, each) were randomized at ≈1 to 3 mos. of age to receive 3 monthly injections of MF59 given with Chiron's HBV (2.5 μg), or Hib/MenC(5/5μg), or Hib/HBV (5/2.5μg) or Hib/MenC/HBV (5/5/2.5μg) vaccines. Controls received licensed HBV vaccine absorbed with aluminum hydroxide (2.5μg, Merck). Antibody responses (geo. means 1 month post-3rd injection) are summarized below. Protective antibody responses to Hib (>1 μg/ml), MenC(bactericidal titers ≥1:32) and HBV (>10 IU/ml) were observed in all animals given the respective combination vaccines. Further, compared to licensed HBV vaccine, MF59 enhanced antibody responses to HBV given alone or with either combination vaccine. These data indicate that, in infant primates, MF59 enhances immunogenicity of novel combination vaccines containing polysaccharide-protein conjugates and HBV. Such combination vaccines have the potential for widespread utility in developed and developing countries.Table

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