Up to now, a two-dose vaccination schedule is always required for the three centrally authorised pandemic H1N1v influenza vaccines Focetria®, Pandemrix® and Celvapan®. With vaccination campaigns ongoing in the European Union, about 5 million people have been vaccinated so far. Following the positive scientific opinion issued by the Committee for Medicinal Products for Human Use (CHMP) at the European Medicines Agency (EMEA), the European Commission authorised a single dose regime of the vaccines Focetria® and Pandemrix® for: 1) adults aged between 18 and 60 years. 2) children and adolescents, from 9 years on, for Focetria®, and from 10 years on for Pandemrix®.