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Oregon ESSENCE: Using ESSENCE for Mass Gathering Surveillance


Syndromic surveillance is the near real-time monitoring of key health indicators in emergency department (ED) and urgent care visits. Oregon ESSENCE tracks the number of visits for specific patient symptoms using chief complaints (what the patient says is the reason for their visit) and discharge diagnosis codes. Visit information is collected from EDs and urgent care centers across the state. Currently, all 60 eligible hospitals are sending ED data every day for syndromic surveillance. Some urgent care centers are currently reporting. See

This guidance document is intended to provide instructions for local ESSENCE users who are using syndromic surveillance as part of mass gathering surveillance efforts. Mass gatherings are sometimes defined as “preplanned public events that are held for a limited time period and attended by more than 25,000 people” (Lombardo, 2008); however, per Oregon Statue (ORS §433.735-433.770), for the purposing of permitting, an outdoor mass gathering is an “actual or reasonably anticipated assembly or more than 3,000 persons” (OHA Regulations 333-039- 0005). In Oregon, ESSENCE has been used to support several sports-related mass gatherings, most recently the 2016 U.S. Olympic Team Track and Field Trials in Lane County (Jagger et al., 2017). In addition to sporting events, syndromic surveillance is now a common public health tool for monitoring health outcomes at political conventions, festivals, and religious gatherings (Al- Tawfiq & Memish, 2014; Hoy et al., 2016; Polkinghorne, Massey, Durrheim, Byrnes, & MacIntyre, 2013; Todkill et al., 2016; Zumla et al., 2016). 

The 2017 eclipse-related mass gatherings present new challenges for Oregon public health authorities and healthcare systems. 

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