Effectiveness of 2018 trivalent influenza vaccine on healthcare professionals

Introduction: Influenza viruses (IV) are responsible for millions of infections each year worldwide. IVs evolves rapidly, by antigenic drift, resulting in the need to update trivalent influenza vaccine (TIV) composition annually, in an effort to match predicted circulating strains. For this reason, studying the immune response to the TIV in the general population is important both for IV epidemiological surveillance and for providing insights into vaccine effectiveness in the different subpopulations.