Research Article: Unacceptably High Mortality Related to Measles Epidemics in Niger, Nigeria, and Chad

Date Published: January 2, 2007

Publisher: Public Library of Science

Author(s): R. F Grais, C Dubray, S Gerstl, J. P Guthmann, A Djibo, K. D Nargaye, J Coker, K. P Alberti, A Cochet, C Ihekweazu, N Nathan, L Payne, K Porten, D Sauvageot, B Schimmer, F Fermon, M. E Burny, B. S Hersh, P. J Guerin, Felicity T Cutts

Abstract: BackgroundDespite the comprehensive World Health Organization (WHO)/United Nations Children’s Fund (UNICEF) measles mortality–reduction strategy and the Measles Initiative, a partnership of international organizations supporting measles mortality reduction in Africa, certain high-burden countries continue to face recurrent epidemics. To our knowledge, few recent studies have documented measles mortality in sub-Saharan Africa. The objective of our study was to investigate measles mortality in three recent epidemics in Niamey (Niger), N’Djamena (Chad), and Adamawa State (Nigeria).Methods and FindingsWe conducted three exhaustive household retrospective mortality surveys in one neighbourhood of each of the three affected areas: Boukoki, Niamey, Niger (April 2004, n = 26,795); Moursal, N’Djamena, Chad (June 2005, n = 21,812); and Dong District, Adamawa State, Nigeria (April 2005, n = 16,249), where n is the total surveyed population in each of the respective areas. Study populations included all persons resident for at least 2 wk prior to the study, a duration encompassing the measles incubation period. Heads of households provided information on measles cases, clinical outcomes up to 30 d after rash onset, and health-seeking behaviour during the epidemic. Measles cases and deaths were ascertained using standard WHO surveillance-case definitions. Our main outcome measures were measles attack rates (ARs) and case fatality ratios (CFRs) by age group, and descriptions of measles complications and health-seeking behaviour. Measles ARs were the highest in children under 5 y old (under 5 y): 17.1% in Boukoki, 17.2% in Moursal, and 24.3% in Dong District. CFRs in under 5-y-olds were 4.6%, 4.0%, and 10.8% in Boukoki, Moursal, and Dong District, respectively. In all sites, more than half of measles cases in children aged under 5 y experienced acute respiratory infection and/or diarrhoea in the 30 d following rash onset. Of measles cases, it was reported that 85.7% (979/1,142) of patients visited a health-care facility within 30 d after rash onset in Boukoki, 73.5% (519/706) in Moursal, and 52.8% (603/1,142) in Dong District.ConclusionsChildren in these countries still face unacceptably high mortality from a completely preventable disease. While the successes of measles mortality–reduction strategies and progress observed in measles control in other countries of the region are laudable and evident, they should not overshadow the need for intensive efforts in countries that have just begun implementation of the WHO/UNICEF comprehensive strategy.

Partial Text: Very significant progress in measles control has been made over the past decade in Africa. The World Health Organization (WHO) and the United Nations Children’s Fund (UNICEF) have developed a comprehensive strategy for sustainable measles mortality reduction, with the goal of a 90% reduction in global measles deaths (compared with 2000 levels) by 2010. The four-pronged strategy focuses on improved routine immunization, providing all children with a second opportunity for measles immunization through either periodic supplemental immunization activities (SIAs) or a routine second dose of measles vaccine, improved measles case management, and careful measles surveillance [1]. The launch of the Measles Initiative in 2001 has helped in the progress made. Partners in the initiative include: the American Red Cross, the United Nations Foundation, the Centers for Disease Control (United States), WHO, and UNICEF. In recent years, measles mortality has declined substantially in Africa: an estimated 216,000 measles deaths in the WHO African Region in 2004 compared with 519,000 in 1999 [2].

With the agreement and collaboration of the respective Ministries of Health, Epicentre conducted three exhaustive household retrospective mortality surveys in Boukoki, Niamey (Niger); Moursal, N’Djamena (Chad); and Dong District, Demsa Local Government Area (Adamawa State, Nigeria). Niamey and N’Djamena are urban areas, whereas Demsa Local Government Area is a rural area.

Epidemic curves and the timing of the surveys are shown in Figures 1–3. Each survey took place when the epidemic was subsiding. Characteristics of study populations are representative of those expected in this region of Africa (Table 1). Fewer than 50 families refused in each survey, with the highest refusal rate being 2% in Dong District.

Our results provide recent estimates from a region of sub-Saharan Africa that has not experienced the progress in measles control observed in other countries of the region. The 2.8%–7.0% CFRs found in our study are as high as those reported in the early 1990s [3,16–20] from these same countries that were included in our surveys. Similar retrospective community studies conducted in Boukoki, Niamey, Niger after measles epidemics estimated an overall CFR of 6.6% in 1991 [16] and a CFR of 2.4% in children aged under 5 y in 1995 [17]. In a rural area in Niger, a retrospective community survey that was performed after the 1991–1992 epidemic identified a CFR of 18.2% in children aged under 5 y [18]. A recent study in Mirriah district in Niger found a CFR of 9.7% [3]. In N’Djamena, a community survey after a measles epidemic in 1993 found a mean CFR of 7.4% in children aged under 5 y [20]. In an urban area of Nigeria in 1995, a CFR of 3.3% was found in the population [19].



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