Abstract
BACKGROUND
A tailor-made serogroup B outer membrane vesicle vaccine was evaluated in the context of a 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 6-8 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 6-weekly intervals.
MAIN OUTCOME MEASURES
Immune response was determined by human complement mediated serum bactericidal assay. Sero-response was a fourfold or greater rise in titre compared to baseline, with baseline titres <4 required to increase to >or=8. Blood samples were taken before vaccination, 6 weeks after dose two, and 4 weeks after dose three. Local and systemic reactions were recorded for 7 days following vaccination.
RESULTS
Sero-response to the candidate vaccine strain, NZ98/254, was demonstrated in 74% of vaccinees (95% CI: 68% to 80% intention-to-treat; 67% to 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).
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