Group A antibody persistence five years after meningococcal polysaccharide vaccination in the Sudan.

Large meningococcal group A epidemics occur periodically in the Sudan, a country within the "meningitis belt" of Sub-Saharan Africa. Immunization with meningococcal polysaccharide vaccine induces protective serum bactericidal titers but little information is available on the duration of protection. Serum samples were obtained from 20 subjects, aged 11-47 years, who resided in the Sudan, and who had participated in a meningococcal polysaccharide immunogenicity study five years earlier.

Serum group a anticapsular antibodies in a Sudanese population immunized with meningococcal polysaccharide vaccine during a group A epidemic.

Background: Vaccination during group A meningococcal epidemics is reported to decrease the number of new cases of disease. However, implementing mass vaccination is often delayed, and little information is available on whether immunity increases in a population vaccinated during an epidemic when exposure to the epidemic strain is common.

Methods: A convenience sample of 134 previously unimmunized persons, ages 3-49 years, were immunized with a meningococcal polysaccharide vaccine.