New zealand epidemic strain meningococcal B outer membrane vesicle vaccine in children aged 16-24 months.
BACKGROUND
New Zealand has experienced an epidemic of Neisseria meningitidis dominated by strain B:4:P1.7b,4 since 1991. Children younger than 5 years are at highest risk. Previous serogroup B outer membrane vesicle (OMV) strain specific vaccines have shown variable efficacy in this age group.


OBJECTIVE
To evaluate the immunogenicity, reactogenicity and safety in 16-24-month-old children of an OMV vaccine developed against the New Zealand epidemic strain.


METHODS
Children (332) aged 16-24 months were randomized to receive the New Zealand candidate vaccine made using strain NZ98/254 (B:4:P1.7b,4) or the Norwegian parent vaccine made using strain 44/76 (B:15:P1.7,16). Vaccines (25 microg/dose) were administered at 0, 6 and 12 weeks in this observer-blind trial. Immune response was measured by serum bactericidal assay and enzyme-linked immunosorbent assay. Sero-response was defined as a 4-fold or greater rise in serum bactericidal antibody titer compared with baseline, with titers <1:4 required to increase to >or=1:8 to be considered a sero-response. Local and systemic reactions were monitored for 7 days after vaccination.


RESULTS
Sero-response against NZ98/254 was achieved after 3 doses in 75% (95% CI: 69-80%) receiving the New Zealand candidate vaccine by both intention to treat (ITT) and per protocol (PP) analyses. In Norwegian parent vaccinees this was seen in 3% (0-12%) (ITT) and 4% (0-13%) (PP). Vaccines were well tolerated with no vaccine-related serious adverse events.


CONCLUSIONS
The New Zealand candidate vaccine administered to these 16-24-month-old children in 3 doses was safe and elicited a promising immune response against the candidate vaccine strain NZ98/254 (N. meningitidis B:4:P1.7b,4) contributing to vaccine licensure for this age group.
Wong
Sharon
S
The University of Auckland, Auckland, New Zealand.
Lennon
Diana
D
Jackson
Catherine
C
Stewart
Joanna
J
Reid
Stewart
S
Crengle
Sue
S
Tilman
Sandrine
S
Aaberge
Ingeborg
I
O'Hallahan
Jane
J
Oster
Philipp
P
Mulholland
Kim
K
Martin
Diana
D
D000907:Antibodies, Bacterial / Q000097:blood*; D001770:Blood Bactericidal Activity; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008589:Meningococcal Infections / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D022401:Meningococcal Vaccines / Q000008:administration & dosage* / Q000276:immunology; D038541:Neisseria meningitidis, Serogroup B / Q000145:classification / Q000276:immunology*; D009520:New Zealand; D016037:Single-Blind Method; D013045:Species Specificity; D016896:Treatment Outcome
D000907:Antibodies, Bacterial; D022401:Meningococcal Vaccines