Delays in notification of infectious disease.

The delays in notifying infectious diseases can have implications on the efficiency of public health intervention, and allowance should be made when interpreting time trends. Data on notification delays of 15 diseases over 30 years in nine Health Authorities in England are presented. Measles is the most rapidly notified (a median delay of five days between onset and notification) and tuberculosis the slowest (median two months). The notification delay has varied between diseases, between Districts and also over time, and appears to have increased in recent years. The differences are attributed to the relative ratity, acuteness and difficulty of diagnosis of the disease, to administrative differences between Districts and to changes in incidence over time.