Surveillance of ambulance dispatch data as a tool for early warning.
Early detection of disease outbreaks is essential for authorities to initiate and conduct an appropriate response. A need for an outbreak detection that monitored data predating laboratory confirmations was identified, which prompted the establishment of a novel symptom surveillance system. The surveillance system monitors approximately 80% of the Danish population by applying an outbreak detection algorithm to ambulance dispatch data. The system also monitors both regional and national activity and has a built-in, switch-on capacity for implementing symptom surveillance reporting in case of an alert. In an evaluation with outbreak scenarios it was found that decreasing the outbreak detection sensitivity from a prediction limit of 95% to one of 99% moderately reduced the time to detection, but considerably diminished the number of false alerts. The system was able to detect an increased activity of influenza-like illness in December 2003 in a timely fashion. The system has now been implemented in the national disease surveillance programme.
Bork
K H
KH
National Centre for Biological Defence, Statens Serum Institut, Copenhagen, Denmark.
Klein
B M
BM
Mølbak
K
K
Trautner
S
S
Pedersen
U B
UB
Heegaard
E
E
D000552:Ambulances; D003718:Denmark / Q000453:epidemiology; D004196:Disease Outbreaks / Q000517:prevention & control; D004631:Emergency Medical Service Communication Systems / Q000639:trends*; D006801:Humans; D018571:Sentinel Surveillance; D013997:Time Factors