Methods for assessing influenza vaccination coverage in target groups (2016)

Influenza causes considerable morbidity and mortality every year. Annual influenza vaccination is the primary means of preventing influenza infection and its complications. Individuals at high risk for negative outcomes from influenza infection are recommended to receive influenza vaccine annually. Target groups for influenza vaccine vary by country. Understanding the extent of vaccine coverage in target groups is essential for planning purposes, assessing the impact of the programme, understanding gaps in coverage and measuring trends over time. This publication outlines different methodologies that can be used to estimate national influenza vaccine coverage among high-risk groups targeted for vaccination. All methodologies presented here include explanations for estimating numeraton and denominator data. Not all methodologies may be useful for all target groups; therefore, countries could consider using different methodologies to estimate vaccine coverage in different target groups.