PLoS ONE (Jan 2016)

A Seroepidemiological Study of Serogroup A Meningococcal Infection in the African Meningitis Belt.

  • Olivier Manigart,
  • Caroline Trotter,
  • Helen Findlow,
  • Abraham Assefa,
  • Wude Mihret,
  • Tesfaye Moti Demisse,
  • Biruk Yeshitela,
  • Isaac Osei,
  • Abraham Hodgson,
  • Stephen Laryea Quaye,
  • Samba Sow,
  • Mamadou Coulibaly,
  • Kanny Diallo,
  • Awa Traore,
  • Jean-Marc Collard,
  • Rahamatou Moustapha Boukary,
  • Oumarou Djermakoye,
  • Ali Elhaji Mahamane,
  • Jean-François Jusot,
  • Cheikh Sokhna,
  • Serge Alavo,
  • Souleymane Doucoure,
  • El Hadj Ba,
  • Mariétou Dieng,
  • Aldiouma Diallo,
  • Doumagoum Moto Daugla,
  • Babatunji Omotara,
  • Daniel Chandramohan,
  • Musa Hassan-King,
  • Maria Nascimento,
  • Arouna Woukeu,
  • Ray Borrow,
  • James M Stuart,
  • Brian Greenwood

DOI
https://doi.org/10.1371/journal.pone.0147928
Journal volume & issue
Vol. 11, no. 2
p. e0147928

Abstract

Read online

The pattern of epidemic meningococcal disease in the African meningitis belt may be influenced by the background level of population immunity but this has been measured infrequently. A standardised enzyme-linked immunosorbent assay (ELISA) for measuring meningococcal serogroup A IgG antibodies was established at five centres within the meningitis belt. Antibody concentrations were then measured in 3930 individuals stratified by age and residence from six countries. Seroprevalence by age was used in a catalytic model to determine the force of infection. Meningococcal serogroup A IgG antibody concentrations were high in each country but showed heterogeneity across the meningitis belt. The geometric mean concentration (GMC) was highest in Ghana (9.09 μg/mL [95% CI 8.29, 9.97]) and lowest in Ethiopia (1.43 μg/mL [95% CI 1.31, 1.57]) on the margins of the belt. The force of infection was lowest in Ethiopia (λ = 0.028). Variables associated with a concentration above the putative protective level of 2 μg/mL were age, urban residence and a history of recent vaccination with a meningococcal vaccine. Prior to vaccination with the serogroup A meningococcal conjugate vaccine, meningococcal serogroup A IgG antibody concentrations were high across the African meningitis belt and yet the region remained susceptible to epidemics.