A SPACE-TIME CRITERION FOR EARLY DETECTION OF EPIDEMICS OF INFLUENZA-LIKE-ILLNESS

Objectives: To develop a method based on a space-time criterion for ea rly detection of epidemics of influenza-like-illness in France. Method s: Since 1984, the French Communicable Diseases computer Network (FCDN ) routinely detects epidemics of influenza-like-illness when the natio nal incidence rate is, for 2 consecutive weeks, above a threshold comp uted by a periodic regression model. It appears that some areas report ed early increases in incidence several weeks before the national epid emic. An optimised space-time criterion allows an early detection of t he epidemic periods. Results: Applying this space-time criterion to th e last 11 epidemics (from 1986), the sensitivity was 0.82 and the spec ificity was 0.99. Conclusion: This simple procedure can be used as an additional tool for early detection of an epidemic taking into account the distribution of new cases in space and time.