Influenza vaccination recommended for all adults aged between 50 and 64 years: conceptual basis and methodological limitations

In the first half of this year, the experts of the Italian Society of Hygiene (SItI), along with those of other National Scientific Societies, agreed with the recommendations made by the USA CDC in 2009, and developed a proposal for a vaccination schedule (Vaccine Schedule for Life), in which influenza vaccination is recommended for all adults aged between 50 and 64 years. In the National Plan for Vaccinal Prevention 2012-2014, which was published just before the issue of the SitI Calendar but concluded earlier (end of 2011), influenza vaccination is recommended “only” for all persons ≥65 years or included in one of the many at-risk categories. The issue is controversial and has generated considerable debate at national and international level. This short note discusses the logical processes and the scientific evidence in support or against the decision to extend the influenza vaccination. The Authors conclude that the epidemiological approach used by SItI experts is appropriate. In any case, further studies on the topic are strongly needed, and their results should be taken into account in the drafting of future vaccination schedules.