Start of regional influenza surveillance for the 2017–2018 season
During the winter months, influenza may infect up to 20% of the population, depending on which viruses are circulating, and cause substantial mortality. People at increased risk for severe disease once infected include the elderly, pregnant women, young children, immunocompromised people and people with chronic underlying medical conditions. These groups represent a significant proportion of the population in the WHO European Region. WHO recommends that everyone at risk of severe disease as a result of infection with influenza, as well as health-care workers, be offered a seasonal influenza vaccine.