The Humanitarian Health Evidence Review

• In total, 6 papers were included in the review. The intervention in each study was either oral polio vaccine (OPV) or inactivated polio vaccine (IPV).
• 2/6 papers described vaccine delivery without any relation to health outcomes, while another significant body of literature focused on refugees in middle and high income countries.
• Only six studies met the inclusion criteria of this review, three of these studies were graded as high quality (O’Reilly 2014, Aaby 2005, Aaby 2002).
• The remaining three studies, while assessing coverage and not directly measuring health outcomes (e.g. virological markers of uptake), were included as the calculation of cost per child is also an outcome of interest (Sheikh 2014, MMWR 2014).
• One high quality retrospective case-control analysis has provided the polio community with amongst its best estimates of how and where to target efforts in these settings (O’Reilly 2014).
• In terms of effectiveness, this decade-long analysis of children -14 years in Afghanistan and Pakistan – indicated a significant reduction in polio and acute flaccid paralysis (AFP) incidence. It also demonstrated that mono- and bivalent formulations of OPV work equally well in this population and setting.
• Two high quality papers from Guinea Bissau provided morbidity and mortality estimates in relation to measles and IPV; both vaccines were part of a RCT that had been severely interrupted due to civil war (Aaby 2002, 2005)

These studies, both presenting data gathered during interruptions due to war, demonstrated that OPV is associated with significantly less mortality and hospitalizations, particularly in children aged 6 months or younger. Further, studies indicate a difference in mortality between males and females but the results are inconclusive overall: one study found a higher morality in females than males for IPV, while another found no difference between males and females for OPV.