Global, regional, and national estimates of influenza burden of disease (BoD) are a key output of the Pandemic Influenza Preparedness (PIP) Partnership Contribution’s high-level implementation plan (HLIP) and are important for developing influenza vaccine policies.
Estimates of the cumulative incidence of seasonal influenza infections can be used to determine key epidemiologic parameters such as the transmissibility of the virus, the proportion of the population that is susceptible to infection following an epidemic, and the risk of death due to influenza infections. These parameters are also important when assessing the risk of pandemic respiratory viruses, such as SARS-CoV-2, as comparisons of key epidemiological characteristics between viruses can provide contexts to understand the potential public health impact of novel respiratory viruses. In addition, economic burden estimates and associated cost benefit analysis are of direct relevance to advocate for and to undertake priority setting for influenza vaccine policies in Member States (MS).
In the past, MS have estimated seasonal influenza disease burden on a limited scale and scope, in specific populations and using diverse methodologies. Expectedly, such studies have had limited impact in terms of policy shifts related to influenza prevention and control. A need has therefore been felt for some time to have a more systematic, standardized, and consistent approach to BoD estimation so as to generate credible evidence for influenza policies in MS and in the region as a whole. Accordingly, WHO SEARO is initiating BoD studies in the South East Asia region, beginning with select MS with good influenza surveillance systems. These studies will be carried out in partnership with WHO HQ under the financial support of the five-year regional CDC-CoAg grant, using the protocols developed by WHO HQ and partners.
In addition to carrying out BoD studies in select MS in this phase, feasibility assessment studies will also be carried out in other MS with the aim of assessing influenza surveillance and identifying data gaps to be addressed for future BoD estimation. Going forward, the initiative also aims at developing regional capacity (through training of a pool of consultants in BoD methodologies/protocols) for supporting MS in the region in carrying out BoD studies.
Through the ‘Burden of influenza disease studies’ project, the WHO’s regional office for South-East aims to narrow the existing gap in understanding influenza disease burden nationally in MS and regionally in WHO’s South East Asia Region It also contributes to evidence generation at the global level while also ensuring that Influenza disease burden estimates are used for public health decisions, such as influenza vaccination