Burden of influenza and impact of seasonal vaccination in Europe - a ten year forecast.

Abstract

Introduction: Influenza is a preventable infectious disease and remains a serious problem for many countries due to its worldwide spread. Despite the often, short duration of illness, it poses a substantial healthcare burden. There is dearth of country-specific data on the burden of flu. Objective: To estimate the burden of influenza and the impact of vaccination in Europe over the next decade. Methods: Our analysis is based on critically- appraised literature evidence that reports seropositive symptomatic events of Influenza. In absence of country-specific reliable data, we derived our estimates from a U.S. based study to 28 EU countries (Sullivan K, 1996). To make valid extrapolations from the U.S. study to European countries, we developed a model using ratios of lower respiratory tract infections risk, reported by the IHME Global Burden of Disease Study. The event rates are adjusted per the risk reduction factor and recent recommendations for seasonal flu vaccine and its coverage. Results: We estimate 17.8 million events of influenza in Europe in 2018. Among the countries we report, event rate is highest in Lithuania and lowest in Luxembourg at 98.9 and 17.4 per 1000. Children under 15 years account for nearly 50% of all events. Due to increasing vaccine uptake, we estimate 2 million fewer flu events by 2028, across the major European countries. Conclusion: Combined with 10-year forecast, our results facilitate identification of countries at risk and opportunities for averting flu in the vulnerable countries. Both increased vaccination coverage and development of vaccines are complementary approaches and will better protect European population from seasonal flu.