Meningococcal disease: risk for international travellers and vaccine strategies

Abstract

International travel and migration facilitate the rapid intercontinental spread of meningococcal disease. Serogroup A and, less so serogroup C, have been responsible for epidemics in the past (mainly in Africa). In recent years, W135 has emerged (first in Saudi Arabia, then in West Africa) as a serogroup that requires attention. Serogroups X and Y are infrequent, but associated with slowly rising trends. There are significant variations in the incidence of meningococcal disease and the distribution of serogroups responsible for meningococcal disease, both geographically and with time. Vaccine strategies need to address this variation, and broad coverage against all serogroups for which vaccines are currently available should be offered to travellers. Tetravalent polysaccharide meningococcal vaccines are limited by their poor immunogenicity in small infants and by the lack of long-term protection. In contrast, the novel tetravalent conjugate vaccine that is currently only available in North America is immunogenic in young infants, induces long-term protection and reduces nasopharyngeal carriage. The tetravalent conjugate meningococcal vaccine will be a leap forward in the control of meningococcal epidemics in affected countries. It will also boost the uptake of meningococcal vaccines in travellers because the duration of protection is longer and it eliminates the problem of immune hyporesponsiveness of serogroup C with repeated dosing. Current vaccine recommendations are to vaccinate all Hajj pilgrims, all travellers to areas with current outbreaks, travellers to the SubSaharan meningitis belt, and individuals with certain medical conditions.