Strategies to improve immunization services in urban Africa.

The urban poor constitute a rapidly increasing proportion of the population in developing countries. Focusing attention on underserved urban slums and squatter settlements will contribute greatly to immunization programme goals, because these areas account for 30-50% of urban populations, usually provide low access to health services, carry a large burden of disease mortality, and act as sources of infection for the city and surrounding rural areas. Improvement of urban immunization programmes requires intersectorial collaboration, use of all opportunities to vaccinate eligible children and mothers, identification of low-coverage neighbourhoods and execution of extra activities in these neighbourhoods, and community mobilization to identify and refer persons for vaccination. Improved disease surveillance helps to identify high-risk populations and document programme impact. New developments in vaccines, such as the high-dose Edmonston-Zagreb vaccine, will allow changes in the immunization schedule that facilitate the control of specific diseases. Finally, operational research can assist managers to conduct urban situation assessments, evaluate programme performance at the "micro" level, and design and monitor interventions.