Measles outbreaks in displaced populations: a review of transmission, morbidity and mortality associated factors

Abstract

BackgroundMeasles is a highly contagious infectious disease with a significant public health impact especially among displaced populations due to their characteristic mass population displacement, high population density in camps and low measles vaccination coverage among children. While the fatality rate in stable populations is generally around 2%, evidence shows that it is usually high among populations displaced by disasters. In recent years, refugees and internally displaced persons have been increasing. Our study aims to define the epidemiological characteristics and risk factors associated with measles outbreaks in displaced populations.MethodsWe reviewed literature in the PubMed database, and selected articles for our analysis that quantitatively described measles outbreaks.ResultsA total of nine articles describing 11 measles outbreak studies were selected. The outbreaks occurred between 1979 and 2005 in Asia and Africa, mostly during post-conflict situations. Seven of eight outbreaks were associated with poor vaccination status (vaccination coverage; 17-57%), while one was predominantly due to one-dose vaccine coverage. The age of cases ranged from 1 month to 39 years. Children aged 6 months to 5 years were the most common target group for vaccination; however, 1622 cases (51.0% of the total cases) were older than 5 years of age. Higher case-fatality rates (>5%) were reported for five outbreaks. Consistent factors associated with measles transmission, morbidity and mortality were vaccination status, living conditions, movements of refugees, nutritional status and effectiveness of control measures including vaccination campaigns, surveillance and security situations in affected zones. No fatalities were reported in two outbreaks during which a combination of active and passive surveillance was employed.ConclusionMeasles patterns have varied over time among populations displaced by natural and man-made disasters. Appropriate risk assessment and surveillance strategies are essential approaches for reducing morbidity and mortality due to measles. Learning from past experiences of measles outbreaks in displaced populations is important for designing future strategies for measles control in such situations.

The effect of social determinants on immunization programs

“…In this regard, measles outbreaks were described in several studies conducted among displaced populations. 21 Most of these outbreaks occurred in post-conflict circumstances, where immunization status, nutrition, living conditions and refugee movements contributed to the transmission, illness and death from the disease. 21 The migration of children between Burkina Faso and Cote D'Ivoire was found to contribute to a measles outbreak in Burkina Faso which occurred despite supplementary measles vaccination given to children in Burkina Faso shortly before the outbreak.…”

Gender differentials in the timing of measles vaccination in rural India

“…Furthermore, regardless of setting, measlesrelated deaths are consistently higher among unvaccinated children. However, despite these benefits, measles immunization rates continue to be sub-optimal in many developing countries, and measles remains a leading cause of childhood morbidity and mortality, particularly among vulnerable populations (Kouadio et al 2010).…”

Health outcomes of crisis driven urban displacement: A conceptual framework

“…Outbreaks of communicable diseases are well and accurately reported for displaced populations but these either focus on refugee/IDP camps or rural displaced populations. 32,33 Similarly, reviews of respiratory infections for crisis-affected populations do not specifically address the problems of the urban displaced. Rather, quantitative data have been gathered from rural refugees and IDPs, refugee camps and non-displaced urban residents during armed conflict.…”