Humanitarian emergencies may result in breakdown of regular health services including routine vaccination programs. Displaced populations including refugees and internally displaced persons are particularly susceptible to outbreaks of communicable diseases such as vaccine-preventable diseases (VPDs). Common VPDs encountered in humanitarian emergencies include measles, polio, and depending on geographical location, meningococcal meningitis, yellow fever, hepatitis A, and cholera. We conducted a review of 50 published articles from 2000 to 2015 concerning VPDs in humanitarian emergencies. This article provides an update on the available literature regarding vaccinations among this highly vulnerable population and describes the unique challenges of VPDs during humanitarian emergencies. Humanitarian emergencies place affected populations at risk for elevated morbidity and mortality from VPDs due to creation or exacerbation of factors associated with disease transmission such as mass population movements, overcrowding, malnutrition, and poor water and sanitation conditions. Vaccination is one of the most basic and critical health interventions for protecting vulnerable populations during emergencies. Growing insecurity, as seen in the increasing number of targeted attacks on health workers in recent years, as well as destruction of cold chain and infrastructure for transportation of supplies, are creating new challenges in provision of life saving vaccines in conflict settings. Population displacement can also threaten global VPD eradication and elimination efforts. While highly effective vaccines and guidelines to combat VPDs are available, the trend of increasing number of humanitarian emergencies globally poses new and emerging challenges in providing vaccination among displaced populations.

Populations affected by humanitarian emergencies may require unique strategies to ensure access to life-saving vaccines and attain sufficiently high population immunity to interrupt virus circulation. Vaccination strategies among displaced populations should not be an afterthought and must be part of the vaccine-preventable disease eradication and elimination initiatives from the start.

Accuracy of self-reported data may be improved by data editing, a mechanism to produce accurate information by excluding inconsistent data based on a set number of predetermined decision rules. We compared data editing methods in the Global Youth Tobacco Survey (GYTS) with other editing approaches and evaluated the effects of these on smoking prevalence estimates. We evaluated 5 approaches for handling inconsistent responses to questions regarding cigarette use: GYTS, do-nothing, gatekeeper, global, and preponderance. Compared with GYTS data edits, the do-nothing and gatekeeper approaches produced similar estimates, whereas the global approach resulted in lower estimates and the preponderance approach, higher estimates. Implications for researchers using GYTS include recognition of the survey's data editing methods and documentation in their study methods to ensure cross-study comparability.