Local surveillance of influenza in the United Kingdom: from sentinel general practices to sentinel cities?

Surveillance of influenza in England and Wales utilises a disparate geographical network of general practices to provide clinical data in the form of weekly consultation rates for influenza and 'influenza-like illness'. This network accurately detects and monitors seasonal influenza activity at national and supra-regional levels. Localised regional and sub-regional epidemics are less easily detected. We describe a localised epidemic of influenza affecting a deprived urban community in the North West of England that was detected by a close knit network of general practices participating in the surveillance of communicable diseases as part of a primary care health needs assessment initiative.