Preventing influenza in younger children.

Influenza is common in infants and children: attack rates vary from 23% to 48% each year during inter-pandemic periods, and are even higher during pandemics. Severe cases occur more frequently in children with underlying chronic diseases; however, epidemiological studies have clearly shown that influenza also causes an excess of medical examinations, drug prescriptions and hospitalizations in otherwise healthy children (particularly those aged <5 years), as well as a considerable number of paediatric deaths. Childhood influenza also has a number of social and economic consequences. However, many European health authorities are still reluctant to include influenza vaccinations in their national vaccination programmes for healthy children because, among other things, there are doubts concerning their real ability to evoke a protective immune response, especially in children in the first years of life. New hope for the solution of these problems has come from the introduction of vaccines containing more antigens and the possibility of intradermal administration. However, further studies are needed to establish whether universal influenza vaccination in the first years of life should be recommended, and with which vaccine.