Emergency Department (ED) and Urgent Care Visits 

Source: Virginia’s syndromic surveillance system, ESSENCE (Electronic Surveillance System for the Early Notification of Community-based Epidemics). 

About: The Virginia Department of Health (VDH) collects and analyzes health data from participating EDs and urgent cares in Virginia. All non-federal acute care hospitals and free-standing emergency care centers report ED visit data to VDH. Urgent care reporting varies throughout the state. Data are for clinical care of patients in healthcare settings. Public health surveillance is a secondary use. When interpreting trends, please consider syndromic surveillance data limitations. 

Case Definition: Visits with a chief complaint indicating gastrointestinal (GI) illness, including abdominal pain, diarrhea, or vomiting. 

Threshold: The GI illness threshold was calculated using data from 2022 to 2024. For each year, VDH identified the consecutive 11 weeks with the lowest mean percent of GI illness visits. The baseline was the mean of the combined 33 weeks (11 weeks from each year). The threshold is defined as the baseline plus two standard deviations, represented by the orange line. The blue line represents the weekly percent of ED and urgent care visits. 

Geography: VDH assigns health region using the patient’s residential zip code. The dashboard includes ED and urgent care visit data at Virginia facilities among Virginia and out-of-state residents. Use the VDH Health District Reference Guide for a list of cities and counties in each region and health district. 

Visit the Syndromic Surveillance page for more ED and urgent care data. 

For questions, email syndromic@vdh.virginia.gov.  

Outbreak Investigations 

Source: Virginia’s outbreak surveillance system (VOSS) 

About: When a Local Health Department (LHD) is notified of an outbreak of any disease, the outbreak is entered into the Virginia Outbreak Surveillance System (VOSS). As the outbreak investigation continues, users update and add data to the outbreak record. Outbreaks are categorized by syndrome: Respiratory, Dermatological, Gastrointestinal, Sepsis, and Other. Gastrointestinal syndrome outbreak data is pulled for this report.  

The person in charge of any residential or day program, service or facility licensed or operated by any agency of the Commonwealth, school, or summer camp is required to report. This includes child care facilities, assisted living facilities, correctional or other detention facilities, mental health programs, and other group settings where outbreaks of illness might occur. 

Anyone required to report in accordance with Virginia’s reportable disease list is also required to report suspected outbreaks to the Health Department. 

Case Definition: Outbreak investigations where the syndrome category is Gastrointestinal and the etiologic agent is Norovirus, Viral Gastroenteritis, and Unknown. 

Earliest Outbreak Report Date: These outbreak investigations are reported based on the Earliest Outbreak Report Date. It is the earliest date from among the following: 1. the date the local health department was notified of the outbreak 2. the date VDH central office staff was notified of the outbreak 3. the date the outbreak investigation began 4. the date the outbreak record was created in the Virginia Outbreak Surveillance System.  

Geography: VDH assigns outbreak investigations to the region based on the address where the outbreak is occurring. Use the VDH Health District Reference Guide for a list of cities and counties in each region and health district.