News headlines this week have certainly raised anxiety over the influenza A/H1N1 (swine flu) pandemic in the United Kingdom, with reports of 17 deaths to date since the national epidemic started in late April, and one of the dead being a 6 year old girl with apparently no pre-existing medical conditions. NHS Direct telephone lines have been swamped in recent days as the epidemic continues to expand and mortality rises.

How serious is the UK epidemic, and what are the likely trends over the coming months as autumn arrives? General practice consultation rates in England for patients presenting with flu-like illness have increased and are now above the threshold for normal seasonal flu activity. The 5-14 year olds remain the age group predominantly affected, with London and the West Midlands being the worst affected regions. Mortality among clinical cases with confirmed influenza A/H1N1 infection is currently between 1 per 200 and 1 per 400. This is a higher figure than that typically seen with seasonal flu, but the true figure per case of infection will be much lower because of a high prevalence of mild symptoms not captured in the current reporting system. Many biases affect these estimates, as reported in the linked article by Garske and colleagues (doi:10.1136/bmj.b2840).1 More detailed retrospective household studies are needed now, with serology to ascertain infection and morbidity. These are planned to take …