Methodology for computing the burden of disease of adverse events following immunization.

PURPOSE: Composite disease burden measures such as disability-adjusted life-years (DALY) have been widely used to quantify the population-level health impact of disease or injury, but application has been limited for the estimation of the burden of adverse events following immunization. Our objective was to assess the feasibility of adapting the DALY approach for estimating adverse event burden. METHODS: We developed a practical methodological framework, explicitly describing all steps involved: acquisition of relative or absolute risks and background event incidence rates, selection of disability weights and durations, and computation of the years lived with disability (YLD) measure, with appropriate estimation of uncertainty. We present a worked example, in which YLD is computed for 3 recognized adverse reactions following 3 childhood vaccination types, based on background incidence rates and relative/absolute risks retrieved from the literature. RESULTS: YLD provided extra insight into the health impact of an adverse event over presentation of incidence rates only, as severity and duration are additionally incorporated. As well as providing guidance for the deployment of DALY methodology in the context of adverse events associated with vaccination, we also identified where data limitations potentially occur. CONCLUSIONS: Burden of disease methodology can be applied to estimate the health burden of adverse events following vaccination in a systematic way. As with all burden of disease studies, interpretation of the estimates must consider the quality and accuracy of the data sources contributing to the DALY computation.

Overlapping topics in advisory reports issued by five well-established European National Immunization Technical Advisory Groups from 2011 to 2014.

National Immunization Technical Advisory Groups (NITAGs) are facing increasingly complex vaccination issues together with a lack of human resources for evidence assessment and data analysis. One way to reduce these burdens could be to share some of the preparatory work across NITAGs. We conducted an inventory of all the advisory reports issued by five well-established European NITAGs from 2011 to 2014 to assess overlaps in issues and activities. A total of 104 advisory reports were retrieved. Advisory reports on the same issues were compared to identify overlapping activities and processes. Advisory reports issued by the five NITAGs showed little overlap in issues and processes. A first step towards efficient collaboration would be to establish an independent platform to provide insight into each NITAG's work and to facilitate the exchange of agendas, assessment frameworks and evidence.