Characterizing Public Health Actions in Response to Syndromic Surveillance Alerts
Fifteen public health units (PHUs) in Ontario, Canada were randomized to the intervention (9) or control (6) arm of a study on their responses to alerts for respiratory syndromes from emergency department data. The intervention PHUs implemented a standard protocol while the control PHUs continued with usual practices. Intervention PHUs were 3 times more likely to check for alternate explanations. Control health units decided that more alerts warranted a response (53%) but most of these were "watchful waiting". For intervention PHUs, the proportion requiring action was lower (18%). Less than 10% of the alerts led to action.