• A Survey on Vaccine Efficacy in the City of Bongor (Chad) and its Operational Consequences for the Vaccination Program

      Luthi, J; Kessler, W; Boelaert, M; Médecins sans Frontières, Bruxelles, Belgique. (Published by WHO, 1997)
      A measles epidemic occurred in the city of Bongor, Chad, from 22 September 1993 to 26 June 1994. A total of 792 patients were hospitalized, with a case fatality rate of 5.2%. After the epidemic, the district management team evaluated the expanded programme on immunization (EPI). Through a cluster survey the attack rate was estimated to be 29.1% (95% confidence interval (CI) = 20.4-37.8%) for the age group 12-59 months (n = 206). For this same age group, the measles immunization coverage was estimated to be 44.2% (95% CI = 34.6-53.8%) and the vaccine efficacy 9.5% (95% CI = 0-41.5%). Several flaws in the logistic handling of the vaccines and especially in the cold chain were identified. These results indicated a serious management problem in the EPI, which the district team then immediately started to rectify. The method used to estimate the immunization coverage and efficacy in the study is rapid and low cost. Also, it is feasible at the district level and permits identification of management problems in the EPI.
    • Late vaccination reinforcement during a measles epidemic in Niamey, Niger (2003-2004).

      Dubray, C; Gervelmeyer, A; Djibo, A; Jeanne, I; Fermon, F; Soulier, M; Grais, RF; Guerin, P J; Epicentre, 8 rue Saint Sabin, 75011 Paris, France. Christine.Dubray@epicentre.msf.org (2006-05-01)
      Low measles vaccination coverage (VC) leads to recurrent epidemics in many African countries. We describe VC before and after late reinforcement of vaccination activities during a measles epidemic in Niamey, Niger (2003-2004) assessed by Lot Quality Assurance Sampling (LQAS). Neighborhoods of Niamey were grouped into 46 lots based on geographic proximity and population homogeneity. Before reinforcement activities, 96% of lots had a VC below 70%. After reinforcement, this proportion fell to 78%. During the intervention 50% of children who had no previous record of measles vaccination received their first dose (vaccination card or parental recall). Our results highlight the benefits and limitations of vaccine reinforcement activities performed late in the epidemic.
    • A long-lasting measles epidemic in Maroua, Cameroon 2008-2009: mass vaccination as response to the epidemic.

      Luquero, Francisco J; Pham-Orsetti, Heloise; Cummings, D A T; Ngaunji, Philippe E; Nimpa, Marcelino; Fermon, Florence; Ngoe, Ndong; Sosler, Stephen; Strebel, Peter; Grais, RFebecca F; et al. (2011-07)
      A measles outbreak occurred in Maroua, Cameroon, from January 2008 to April 2009. In accordance with recent World Health Organization guidelines, an outbreak-response immunization (ORI) was conducted in January 2009. The aim of this study was to investigate the causes of the epidemic in order to guide vaccination strategies.
    • Measles vaccine effectiveness in standard and early immunization strategies, Niger, 1995.

      Kaninda, A V; Legros, D; Jataou, I M; Malfait, P; Maisonneuve, M; Paquet, C; Moren, A; Epicentre, Paris, France. epimail@epicentre.msf.org (1998-11)
      BACKGROUND: An Expanded Programme on Immunization was started in late 1987 in Niger, including vaccination against measles with one dose of standard titer Schwarz vaccine given to infants after 9 months of age. During epidemics an early two-dose strategy was implemented (one dose between 6 and 8 months and one dose after 9 months). From January 1, 1995, until May 7, 1995, 13 892 measles cases were reported in Niamey, Niger. METHODS: A retrospective cohort study was conducted in a crowded area of Niamey at the end of the outbreak to assess the effectiveness of measles vaccine in standard (after 9 months) and early (before 9 months) immunization strategies under field conditions. RESULTS: Highest measles incidence rates were observed among children <1 year of age. Vaccine effectiveness estimates increased with age at vaccination from 78% with a single dose administered at 6 months of age to 95% at 9 months. Vaccine effectiveness with the early two dose strategy was 93%. CONCLUSIONS: Immunization with a single dose of standard titer Schwarz vaccine before 9 months of age provided higher clinical protection than expected from seropositivity studies. The early two dose strategy is justified in contexts where measles incidence is high before 9 months of age. Our results raise the issue of lowering the recommended age for measles vaccination in developing countries.
    • War, drought, malnutrition, measles--a report from Somalia.

      Cabrol, J-C; Doctors without Borders/Médecins sans Frontières, Geneva. (2011-11-17)