Conflits et urgences humanitaires

Le sous-thème «Conflits et urgences humanitaires» contient des éléments de preuve sur l’importance de la vaccination dans les situations de crise telles que les camps de réfugiés, les zones de guerre et les communautés touchées par des catastrophes naturelles. Les facteurs qui augmentent le risque et la gravité des maladies infectieuses telles que la malnutrition, la pauvreté, la surpopulation, la complication de problèmes de santé et l’accès minimal ou inexistant aux médicaments et aux services de traitement sont fréquents et renforcent l’importance des efforts de prévention des maladies tels que la vaccination.

7 Key Concepts

Key Evidence: A two-dose schedule of rotavirus vaccine was estimated to be cost-effective in Somalia, where more than 20 years of civil conflict have significantly damaged the health system and vaccine coverage is exceedingly low. Researchers estimate that in 2012, routine use of rotavirus vaccine, even at low coverage rates, would have averted nearly 25% of deaths due to rotavirus diarrhea in Somali children under one year of age.

View Publication >

Key Evidence: Adding a birth dose of hepatitis B vaccine to routine immunization of refugees in Africa -- who have particularly high infection rates -- is a highly cost-effective means of reducing transmission of the infection thus strengthening the overall global health security among these mobile, vulnerable populations.

View Publication >

Key Evidence: Children under 5 years of age bear the greatest burden of indirect conflict-associated mortality (indirect mortality results from disruption of health services including immunization, food insecurity, and high risk living conditions such as those found in refugee camps). The leading causes of child death in these circumstances include respiratory infections, diarrhea, measles, malaria, and malnutrition.

View Publication >

Key Evidence: Respiratory infections and diarrhea are the leading causes of death during humanitarian emergencies according to a 2016 review of vaccine-preventable diseases and the use of immunizations during complex humanitarian emergencies.

View Publication >

Key Evidence: Mass displacement of people during a complex humanitarian emergency can trigger a "cascade" of risk factors for communicable disease outbreaks, including a breakdown in health services (such as disease surveillance and immunization services); over-crowding (increasing disease transmission rates); inadequate water, sanitation and hygiene; and exposure of displaced population to endemic diseases for which they have no immunity.

View Publication >

Key Evidence: During the conflict in Yemen, efforts spearheaded by WHO, with coordination among partners and effective use of resources, especially GAVI, resulted in continued high pentavalent vaccine coverage decreasing only 3% from 2010 to 2015. Yemen also remained polio-free through 2015 and smoothly introduced two new vaccines (MR and IPV).

Key Evidence: During the humanitarian crisis in the Syrian Arab Republic, the constant support from WHO, UNICEF, and local NGOs resulted in immunizations against VPDs reaching over 90% of children.

View Publication >

Key Evidence: An analysis conducted in areas of Ethiopia with high proportions of refugees found that high measles vaccination coverage was linked to lower rates of acute malnutrition (wasting) in children under five. For each percentage point increase in measles vaccination coverage, there was a 0.65% decrease in the rate of acute malnutrition in these areas.

From the VoICE Editors: The analysis was conducted on data from more than 150 nutrition surveys.

View Publication >

Key Evidence: Malnutrition is a leading contributor to morbidity and mortality during humanitarian emergencies, and a cyclical relationship exists between malnutrition and infectious diseases. Universal immunization programs have been shown to improve the height and weight measurement markers associated with malnutrition.

View Publication >

Key Evidence: Somali refugee children in Kenya were nearly 60 times more likely than children of the main ethnic group in the study (Kikuyu) to not have received any childhood immunization and more than twice as likely to have not completed their vaccinations. Although Somali children made up less than 8% of the sample, they accounted for nearly half of all non-vaccinated children.

From the VoICE Editors: This study used data from Kenya's Demographic and Health Survey data.

View Publication >

Key Evidence: Girls from refugee families in Denmark were 40-56% less likely to receive HPV vaccine through 2 free-of-charge immunization programs than Danish-born girls, and the differences remained significant when income was taken into account. The odds of being vaccinated were lowest for refugees in the country ≤5 years and those from certain countries or regions, indicating the need to reduce cultural, social, and information barriers to immunization, as well as assess immunization programs across increasingly ethnically diverse societies.

View Publication >

Key Evidence: Screening tests given to more than 300 newly-arrived economic migrants and asylum seekers in Italy -- the majority from sub-Saharan Africa -- found high rates of chronic hepatitis B infection and latent and active tuberculosis (with 8% having signs of current infection or active TB). These findings underscore the important of universal screening for infectious diseases for all newly-arrived migrants.

View Publication >

Key Evidence: Antibody screening of asylum seekers arriving in Germany found that few subgroups, such as people from the same country, were sufficiently protected against measles, rubella, and varicella, and that the majority of adolescents and adults would benefit from immunizations. The serology screening results were used to target specific high-risk groups (for example, people from certain countries and age groups) for vaccination as a cost-savings measure, which proved successful in managing varicella outbreaks at refugee reception centers.

View Publication >

Key Evidence: Nearly one-third of children and adolescents seeking asylum in Denmark were not adequately vaccinated upon their arrival, with Afghans and Eritreans having the lowest vaccination rates. This points to the need for initiatives targeted to this population to promote immunization and improve access to health services.

View Publication >

Key Evidence: In a study modeling the cost-effectiveness of vaccination campaigns in Somalia – the country with the second largest number of refugees in 2012 – the use of Hib vaccine, PCV10, or both Hib and PCV10 were all found to be cost effective means to prevent excess morbidity and mortality from pneumonia in young Somali children. Such a vaccination campaign could conservatively reduce pneumonia cases and deaths by nearly 20%.

View Publication >

Key Evidence: Children living in the Yida refugee camp in South Sudan in 2013 were found to have an elevated rate of pneumonia infections likely due to malnutrition, overcrowding, and inadequate shelter. Using these data, the CDC estimated that the use of Hib and pneumococcal vaccines in children under 2 years of age in the camp would be cost-effective under all dosing scenarios evaluated. Medecines Sans Frontiers (MSF) provided medical services to this refugee camp and found delivery of these vaccines to be feasible and effective in this setting.

View Publication >

Key Evidence: The ongoing conflict in Syria has caused the breakdown of immunization services, leading to outbreaks of vaccine preventable diseases in the region and the re-emergence of polio in Syria for the first time in 15 years. The potential for polio to re-emerge in neighboring areas with low coverage of inactivated polio vaccine (IPV) threatens the success of global efforts to eradicate polio.

View Publication >

Key Evidence: Researchers investigating the causes of a measles outbreak in Burkina Faso that occurred despite a recent mass vaccination campaign found that migration to and from Cote d'Ivoire was a major risk factor for children. Unvaccinated children who developed measles were 8.5x more likely to have recently traveled to Cote d'Ivoire than unvaccinated children who had not traveled across the border. Children returning to Burkina Faso after a period of time in Cote d'Ivoire were less likely to have been vaccinated due to low routine coverage of measles vaccines in Cote d'Ivoire. Conversely, unvaccinated children from Burkina Faso who traveled to Cote d'Ivoire and returned were more likely to be exposed to measles and thus had a higher rate of disease than children who never visited Cote d'Ivoire.

View Publication >

Key Evidence: In a study of the overlap between complex humanitarian emergencies and disease outbreaks, researchers found that more than 40% of complex emergencies that occurred between 2005-2014 were associated with an outbreak of infectious disease, with a high likelihood that the outbreak was vaccine-preventable.

View Publication >

Key Evidence: The influx of Syrian refugees into Turkey as a result of the Syrian civil war has led to a re-emergence of several infectious diseases in Turkey, including vaccine-preventable diseases, such as measles (930 cases reported among refugees over 4 years), tuberculosis and hepatitis A.

View Publication >

Key Evidence: An outbreak of wild polio virus began two years after the onset of the civil war in Syria and subsequently spread to Iraq, causing a total of 38 cases (36 in Syria). Factors leading to the outbreak included a decline in polio surveillance and in polio vaccination coverage (from 83% for 3 doses of oral polio vaccine pre-war in Syria to 47-52%).

View Publication >

Key Evidence: The humanitarian emergency in Venezuela, and resulting collapse of its primary health care infrastructure, has caused measles and diphtheria to reemerge -- disproportionately affecting indigenous populations -- and to spread to neighboring countries. This sets the stage for the potential reemergence of polio. The re-establishment of measles as an endemic disease in Venezuela (with >5,500 confirmed cases) and its spread to neighboring countries threaten the measles-free status.

View Publication >

Key Evidence: Insecurity resulting from armed conflict, political instability, or social disruption increases the risk of communicable disease outbreaks during complex humanitarian emergencies by inhibiting populations' access to health services, disrupting activities such as immunization and surveillance that prevent the spread of diseases, and making adequate humanitarian responses more difficult.

View Publication >

Key Evidence: Large measles outbreaks occurred in Lebanon and Jordan, following an influx of Syrian refuges migrating to escape conflict. In Lebanon, the measles incidence increased 200-fold in one year following high migration. There were 2.1 measles cases per million population in Lebanon in 2012; this increased to 411 cases per million in 2013.

View Publication >