Epidemiology of pathogenic Neisseria meningitidis serogroup B serosubtypes in Malta: implications for introducing PorA based vaccines.
OBJECTIVE
To describe the epidemiology of the serosubtypes of Neisseria meningitidis serogroup B (MenB) in the most densely populated area in Europe and to review the MenB Porin A (PorA) based outer membrane vesicle (OMV) vaccines that could provide the broadest protection.


METHODS
Active surveillance of invasive meningococcal disease in a population of 400,000 inhabitants in Malta from 1999 to 2006. Serogroup B isolates were serosubtyped and analysed by age and year. The suitability of OMV vaccines was then assessed.


RESULTS
Laboratory confirmation of invasive meningococcal disease was obtained in 48% (79/163) of notified cases. Serogroup B caused the majority of invasive meningococcal disease (76%, 60/79) with the greatest disease burden occurring in 0-14-year-old children (73%, 44/60). MenC caused 14% (11/79) of cases. The most prevalent MenB serotype:serosubtype combination was B:4:P1.19,15 which constituted 59% (34/58) of all phenotypeable MenB isolates. The PorA epitopes P1.15 and P1.19, detected in 74% (43/58) of isolates, were significantly more prevalent than serosubtypes with other PorA epitopes (chi(2): 7.18, P<0.01).


CONCLUSIONS
An assessment of the usefulness of a MenB OMV vaccine in Malta requires further research. The wild-type OMV vaccine developed by the Finlay Institute (FI) in Cuba could potentially be used to control an outbreak with a MenB P1.19,15 clone. A multivalent OMV vaccine would however be needed for broader protection against the endemic heterogenous MenB strains. A serogroup B vaccine incorporating more conserved proteins than PorA would be more suitable for comprehensive control of meningococcal B disease.
Pace
David
D
Department of Paediatrics, Mater Dei Hospital, MSD, Malta. dpace@mail.global.net.mt
Cuschieri
Paul
P
Galea Debono
Anthony
A
Attard-Montalto
Simon
S
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008319:Malta / Q000453:epidemiology; D008589:Meningococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000517:prevention & control; D022401:Meningococcal Vaccines; D008875:Middle Aged; D038541:Neisseria meningitidis, Serogroup B / Q000145:classification* / Q000302:isolation & purification / Q000472:pathogenicity*; D018272:Porins; D015995:Prevalence; D012703:Serotyping; D055815:Young Adult
D022401:Meningococcal Vaccines; D018272:Porins; C057699:porin protein, Neisseria