Syndromic Surveillance ofNorovirusUsing over the Counter Sales of Medications related to Gastrointestinal Illness

Abstract

OBJECTIVE: To assess whether over-the-counter (OTC) sales of gastrointestinal illness (GI)-related medications are associated with temporal trends of reportable community viral, bacterial and parasitic infections.METHODS: The temporal patterns in weekly and seasonal sales of nonprescription products related to GI were compared with those of reportable viral, bacterial and parasitic infections in a Canadian province.RESULTS: Temporal patterns of OTC product sales andNorovirusactivity were similar, both having highest activity in the winter months. In contrast, GI cases from both bacterial and parasitic agents were highest from late spring through to early fall.CONCLUSIONS: Nonprescription sales of antidiarrheal and antinauseant products are a good predictor of communityNorovirusactivity. Syndromic surveillance through monitoring of OTC product sales could be useful as an early indicator of theNorovirusseason, allowing for appropriate interventions to reduce the number of infections.