Advances in measuring influenza burden of disease

Influenza is a global public health threat, with seasonal and pandemic influenza resulting in substantial impact on health, the economy and society. The World Health Organization (WHO) has recently estimated that every year, 290 000 to 650 000 deaths are associated with respiratory diseases from seasonal influenza.1 This estimate takes into account findings from recent influenza respiratory mortality studies, including a study conducted by Iuliano et al.2 Many highincome countries (HICs) that have invested in measuring the impact of influenza epidemics and the costeffectiveness of interventions against influenza have also spent substantial resources in preventing spread and mitigating health outcomes through vaccination, clinical management of severe cases and other public health measures. At the same time, many lowand middleincome countries (LMICs), especially those in the tropics, are grappling with understanding the impact of influenza in their local setting, and to determine whether such interventions are costeffective visàvis interventions for other diseases.3 Furthermore, LMICs are likely to have the highest burden of influenza in children, but these are also the countries with the least data available.4