An influenza pandemic has recently been declared, involving the novel A(H1N1) 'swine flu' virus. This has spread to almost 100 countries worldwide in less than two months, causing widespread disease so far in Mexico, USA and Canada. It is highly likely that over the next 12 months, many countries including the UK will be affected by widespread illness. In the UK this wave of intense flu activity is most likely to occur in late autumn 2009.