MEASLES EPIDEMIC IN THE URBAN-COMMUNITY OF NIAMEY - TRANSMISSION PATTERNS, VACCINE EFFICACY AND IMMUNIZATION STRATEGIES, NIGER, 1990 TO 1991

From October 1, 1990, until April 28, 1991, 13 578 cases of measles we re reported in the urban community of Niamey, Niger. Vaccine coverages (one dose of Schwarz vaccine given after 9 months) in urban community of Niamey were, respectively, 63% at the age of 12 months and 73% at 24 months before the epidemic. Incidence rates were the highest among children ages 6 to 8 months and 9 to 11 months and 22% of the cases we re less than 1 year old. Vaccine efficacy estimates ranged from 86 to 94% according to age groups and the method used (screening method, cas e control study, retrospective cohort study). The risk of transmission of illness increased with the intensity of contact with a case. Conta ct with a health facility 7 to 22 days before onset of rash was not a risk factor. Seasonal migrants in Niamey were more likely to develop m easles. Recommendations included implementation of an early two dose s chedule of measles immunization during the outbreak, vaccination offer ed at each contact with a health facility, radio and television advert ising for measles immunization and distribution of vitamin A to all me asles cases.