A tailor-made serogroup B outer membrane vesicle vaccine was evaluated in the context of an serogroup B meningococcal epidemic dominated by Neisseria meningitidis strain B:4:P1.7b,4.
Objective: To determine the safety, reactogenicity, and immunogenicity in infants aged 6 to 8 months of a Meningococcal B vaccine developed against the New Zealand epidemic strain.
Design, Setting, and Participants: Observer-blind, randomised, controlled trial conducted in 296 healthy infants in Auckland, New Zealand.
Intervention: Infants were randomised 4:1 to receive three doses of New Zealand candidate vaccine (epidemic strain NZ98/254, B:4:P1.7b,4) or Meningococcal C conjugate vaccine at six weekly intervals.
Main Outcome Measures: Immune response was determined by human complement mediated serum bactericidal assay. Sero-response was a four-fold or greater rise in titre compared to baseline, with baseline titres < 4 required to increase to ≥8. Blood samples were taken pre-vaccination, 6 weeks after dose two, and 4 weeks after dose three. Local and systemic reactions were recorded for 7 days after vaccination.
Results: Sero-response to the candidate vaccine strain, NZ98/254, was demonstrated in 74 % (95%CI: 68-80% intention-to-treat; 67-79% per protocol) after three doses of New Zealand candidate vaccine. No Meningococcal C conjugate vaccine recipients were sero-responders to NZ98/254 after three doses. Both vaccines were well tolerated with no vaccine related serious adverse events.
Conclusions: Our data indicate that the New Zealand candidate vaccine administered in three doses to this group of 6-8 month old infants was safe and immunogenic against the candidate vaccine strain NZ98/254 (Neisseria meningitidis B:4:P1.7b,4).