The first cases of pandemic influenza A (H1N1) 2009 infection were seen in Mexico in March 2009. Since then, it is thought to have been responsible for at least 18,337 deaths globally. Owing to the young age of fatalities, there have been an estimated 2 million years of life lost, which is comparable to the previous pandemics of 1957 and 1968. In this article, we consider the available data on a monovalent inactivated split-virion AS03-adjuvanted pandemic influenza A (H1N1) vaccine, Pandemrix™ (GlaxoSmithKline, Rixensart, Belgium). At present, Pandemrix appears to be highly immunogenic in all age groups, including children and infants under 3 years of age, with an acceptable safety profile in the context of an influenza pandemic. However, owing to the novel adjuvant, further studies on the safety, immunogenicity and vaccine effectiveness of Pandemrix together with robust post-marketing surveillance are required.