The European Commission has just approved the prepandemic vaccine Prepandrix from GlaxoSmithKline, making the London-based company the first to receive the go-ahead to market. Novartis of Basel, on the other hand, recently withdrew a marketing application for its own prepandemic flu vaccine, Aflunov. The European Medicines Agency's Committee for Medicinal Products for Human Use asked for more data but Novartis could not supply this within the time frame required. Prepandrix provides protection against current H5N1 strains and would be used before and in the early stages of a pandemic. The US government has placed an order for Prepandrix, as have Switzerland and Finland. But a new version of the bird flu virus has been found that could also spark a pandemic: the H7N2 strain, which spreads rapidly among mammals. In the event of a pandemic caused by an H5 viral strain, the prepandemic H5 vaccine may offer a degree of cross-protection, but if the virus is from another family, such vaccines are unlikely to be effective, says Nick Phin, consultant in health protection at the UK's Health Protection Agency. The World Health Organization (WHO) is not planning to stockpile the prepandemic vaccine. “We don't know if the next pandemic will be caused by H5N1, H2, H7 or H9 virus,” says Marie-Paule Kieny, the WHO director for initiative in vaccine research.