Syndromic Surveillance among Evacuees at a Houston "Megashelter" following Hurricane Harvey

In the aftermath of Hurricane Harvey in 2017, thousands of residents in the Houston area sought refuge at a convention center "megashelter". Out of concern for the possibility of communicable diseases spreading rapidly in the crowded shelter, we conducted syndromic surveillance to monitor the health of evacuees using a digital drop-in cot-survey. The cot-to-cot survey design rapidly assessed evacuees to determine if they were experiencing any symptoms of illness each night from 1-7 September 2017. While no outbreak of a specific infection was identified during the surveillance period, runny nose, congestion, cough, achy muscles and joints, anxiety, and depression were the most commonly reported symptoms. Out of the total shelter population, 38% of adults reported symptoms compared to 25% of children (<= 18 years). The cot survey took a median of 5.2 min per interview, and the daily participation rate increased throughout the surveillance period starting at 89% and ending at 96% on the last day. The success of this public health response was due, in part, to the effectiveness of survey design and the dissemination of real-time data to the health departments. Digital cot surveys can improve emergency response sustainability, interoperability among emergency responders, and improve evacuee participation.