• A cluster randomized non-inferiority field trial on the immunogenicity and safety of tetanus toxoid vaccine kept in controlled temperature chain compared to cold chain

      Juan-Giner, A; Domicent, C; Langendorf, C; Roper, M H; Baoundoh, P; Fermon, F; Gakima, P; Zipursky, S; Tamadji, M; Grais, RF (2014-09-23)
      In resource-poor settings, cold chain requirements present barriers for vaccine delivery. We evaluated the immunogenicity and safety of tetanus toxoid (TT) vaccine in "Controlled Temperature Chain" (CTC; up to 40°C for <30 days before administration), compared to standard cold chain (SCC; 2-8°C). Prior to the study, stability parameters of TT-CTC were shown to meet international requirements.
    • Continuing effectiveness of serogroup a meningococcal conjugate vaccine, Chad, 2013

      Gamougam, K; Daugla, D M; Toralta, J; Ngadoua, C; Fermon, F; Page, A-L; Djingarey, M H; Caugant, D A; Manigart, O; Trotter, C L; et al. (Center for Disease Control, 2015-01-01)
      In 2011, vaccination with a serogroup A meningococcal polysaccharide conjugate vaccine was implemented in 3 of 23 regions in Chad. Cases of meningitis declined dramatically in vaccinated areas, but an epidemic continued in the rest of Chad. In 2012, the remaining Chad population was vaccinated, and the epidemic was halted.
    • Effect of a serogroup A meningococcal conjugate vaccine (PsA-TT) on serogroup A meningococcal meningitis and carriage in Chad: a community trial

      Daugla, D M; Gami, J P; Gamougam, K; Naibei, N; Mbainadji, L; Narbé, M; Toralta, J; Kodbesse, B; Ngadoua, C; Coldiron, M E; et al. (Elsevier, 2013-09-11)
      A serogroup A meningococcal polysaccharide-tetanus toxoid conjugate vaccine (PsA-TT, MenAfriVac) was licensed in India in 2009, and pre-qualified by WHO in 2010, on the basis of its safety and immunogenicity. This vaccine is now being deployed across the African meningitis belt. We studied the effect of PsA-TT on meningococcal meningitis and carriage in Chad during a serogroup A meningococcal meningitis epidemic.
    • Estimating transmission intensity for a measles epidemic in Niamey, Niger: lessons for intervention.

      Grais, RF; Ferrari, M J; Dubray, C; Bjørnstad, O N; Grenfell, B T; Djibo, A; Fermon, F; Guerin, P J; Epicentre, 8 rue Saint Sabin, 75011 Paris, France. rebecca.grais@epicentre.msf.org (Elsevier, 2006-09)
      The objective of this study is to estimate the effective reproductive ratio for the 2003-2004 measles epidemic in Niamey, Niger. Using the results of a retrospective and prospective study of reported cases within Niamey during the 2003-2004 epidemic, we estimate the basic reproductive ratio, effective reproductive ratio (RE) and minimal vaccination coverage necessary to avert future epidemics using a recent method allowing for estimation based on the epidemic case series. We provide these estimates for geographic areas within Niamey, thereby identifying neighbourhoods at high risk. The estimated citywide RE was 2.8, considerably lower than previous estimates, which may help explain the long duration of the epidemic. Transmission intensity varied during the course of the epidemic and within different neighbourhoods (RE range: 1.4-4.7). Our results indicate that vaccination coverage in currently susceptible children should be increased by at least 67% (vaccine efficacy 90%) to produce a citywide vaccine coverage of 90%. This research highlights the importance of local differences in vaccination coverage on the potential impact of epidemic control measures. The spatial-temporal spread of the epidemic from district to district in Niamey over 30 weeks suggests that targeted interventions within the city could have an impact.
    • Global practices of meningococcal vaccine use and impact on invasive disease

      Ali, A; Jafri, R Z; Messonnier, N; Tevi-Benissan, C; Durrheim, D; Eskola, J; Fermon, F; Klugman, K P; Ramsay, M; Sow, S; et al. (W.S. Maney & Son Ltd, 2014-01)
      A number of countries now include meningococcal vaccines in their routine immunization programs. This review focuses on different approaches to including meningococcal vaccines in country programs across the world and their effect on the burden of invasive meningococcal disease (IMD) as reflected by pre and post-vaccine incidence rates in the last 20 years. Mass campaigns using conjugated meningococcal vaccines have lead to control of serogroup C meningococcal disease in the UK, Canada, Australia, Spain, Belgium, Ireland, and Iceland. Serogroup B disease, predominant in New Zealand, has been dramatically decreased, partly due to the introduction of an outer membrane vesicle (OMV) vaccine. Polysaccharide vaccines were used in high risk people in Saudi Arabia and Syria and in routine immunization in China and Egypt. The highest incidence region of the meningitis belt initiated vaccination with the serogroup A conjugate vaccine in 2010 and catch-up vaccination is ongoing. Overall results of this vaccine introduction are encouraging especially in countries with a moderate to high level of endemic disease. Continued surveillance is required to monitor effectiveness in countries that recently implemented these programs.
    • 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.
    • Local discrepancies in measles vaccination opportunities: results of population-based surveys in Sub-Saharan Africa

      Grout, L; Conan, N; Juan Giner, A; Hurtado, N; Fermon, F; N'goran, A; Grellety, E; Minetti, A; Porten, K; Grais, RF (BioMed Central Ltd, 2014)
      The World Health Organization recommends African children receive two doses of measles containing vaccine (MCV) through routine programs or supplemental immunization activities (SIA). Moreover, children have an additional opportunity to receive MCV through outbreak response immunization (ORI) mass campaigns in certain contexts. Here, we present the results of MCV coverage by dose estimated through surveys conducted after outbreak response in diverse settings in Sub-Saharan Africa.
    • Measles in Democratic Republic of Congo: an outbreak description from Katanga, 2010--2011

      Grout, L; Minetti, A; Hurtado, N; François, G; Fermon, F; Chatelain, A; Harczi, G; Ngoie, J; N Goran, A; Luquero, F J; et al. (BioMed Central (Springer Science), 2013-05-22)
      BACKGROUND: The Democratic Republic of Congo experiences regular measles outbreaks. From September 2010, the number of suspected measles cases increased, especially in Katanga province, where Medecins sans Frontieres supported the Ministry of Health in responding to the outbreak by providing free treatment, reinforcing surveillance and implementing non-selective mass vaccination campaigns. Here, we describe the measles outbreak in Katanga province in 2010--2011 and the results of vaccine coverage surveys conducted after the mass campaigns. METHODS: The surveillance system was strengthened in 28 of the 67 health zones of the province and we conducted seven vaccination coverage surveys in 2011. RESULTS: The overall cumulative attack rate was 0.71% and the case fatality ratio was 1.40%.The attack rate was higher in children under 4 and decreased with age. This pattern was consistent across districts and time. The number of cases aged 10 years and older barely increased during the outbreak. CONCLUSIONS: Early investigation of the age distribution of cases is a key to understanding the epidemic, and should guide the vaccination of priority age groups.
    • Measles outbreak response immunization is context-specific: insight from the recent experience of médecins sans frontières.

      Minetti, A; Bopp, C; Fermon, F; François, G; Grais, RF; Grout, L; Hurtado, N; Luquero, F J; Porten, K; Sury, L; et al. (PLoS, 2013-11)
      Andrea Minetti and colleagues compare measles outbreak responses from the Democratic Republic of the Congo and Malawi and argue that outbreak response strategies should be tailored to local measles epidemiology. Please see later in the article for the Editors' Summary.
    • Outbreak response immunisation: the experience of Chad during recurrent measles epidemics in 2005 and 2010

      Guerrier, G; Guerra, J; Fermon, F; Talkibing, W B; Sekkenes, J; Grais, RF; Epicentre, Paris, France; Medecins Sans Frontieres-Paris, France; Ministry of Health, N'Djamena, Chad (Elsevier, 2011-12)
    • Performance of Small Cluster Surveys and the Clustered LQAS Design to estimate Local-level Vaccination Coverage in Mali

      Minetti, A; Riera-Montes, M; Nackers, F; Roederer, T; Koudika, M H; Sekkenes, J; Taconet, A; Fermon, F; Touré, A; Grais, RF; et al. (2012-08-12)
    • Time is (still) of the essence: quantifying the impact of emergency meningitis vaccination response in Katsina State, Nigeria.

      Ferrari, M J; Fermon, F; Nackers, F; Llosa, A; Magone, C; Grais, RF (Oxford University Press, 2014-09-05)
      In 2009, a large meningitis A epidemic affected a broad region of northern Nigeria and southern Niger, resulting in more than 75 000 cases and 4000 deaths. In collaboration with state and federal agencies, Médecins Sans Frontières (MSF) intervened with a large-scale vaccination campaign using polysaccharide vaccine. Here the authors analyze the impact (cases averted) of the vaccination response as a function of the timing and coverage achieved.
    • Use of Lot Quality Assurance Sampling (LQAS) to estimate vaccination coverage helps guide future vaccination efforts.

      Alberti, K; Guthmann, J P; Fermon, F; Nargaye, K D; Grais, RF; Epicentre, 8 rue Saint Sabin, 75011 Paris, France. kalberti@epicentre.msf.org (Elsevier, 2008-03)
      Inadequate evaluation of vaccine coverage after mass vaccination campaigns, such as used in national measles control programmes, can lead to inappropriate public health responses. Overestimation of vaccination coverage may leave populations at risk, whilst underestimation can lead to unnecessary catch-up campaigns. The problem is more complex in large urban areas where vaccination coverage may be heterogeneous and the programme may have to be fine-tuned at the level of geographic subunits. Lack of accurate population figures in many contexts further complicates accurate vaccination coverage estimates. During the evaluation of a mass vaccination campaign carried out in N'Djamena, the capital of Chad, Lot Quality Assurance Sampling was used to estimate vaccination coverage. Using this method, vaccination coverage could be evaluated within smaller geographic areas of the city as well as for the entire city. Despite the lack of accurate population data by neighbourhood, the results of the survey showed heterogeneity of vaccination coverage within the city. These differences would not have been identified using a more traditional method. The results can be used to target areas of low vaccination coverage during follow-up vaccination activities.