BACKGROUND: Rapid detection and reporting of human infections with novel influenza A viruses is important for prompt awareness of viruses with pandemic potential and to accelerate an effective public health response. We aimed to increase detection of infections using a text-based illness monitoring (TIM) system and evaluate the utility for use in future outbreaks of novel influenza viruses.
METHODS: During an ongoing outbreak of influenza A(H3N2) variant (H3N2v) virus infections among agricultural fair attendees in Michigan in July and August 2016, we piloted a newly developed TIM system for active surveillance of illness among households of animal exhibitors at nine fairs meeting predefined eligibility criteria. Enrolled households received automated daily texts during and for 10 days following the fair asking about any illness among household members; reports of illness were investigated by local health departments. To understand the utility of the system and identify areas for improvement, we monitored enrollment and trends in participation, distributed a web-based survey to exhibitors from participating fairs, and conducted interviews with participating health departments.
RESULTS: Out of an estimated 500 animal exhibitor households, 87 households, representing approximately 384 household members, enrolled. Household participation rates varied by fair (3–86%, median: 13%). Of 384 household members, 22 (6%) persons reported illness symptoms. Of those ill, five (23%) were tested for influenza A(H3N2v) virus; testing practices varied by jurisdiction. Two of the five tested were positive for H3N2v virus. The number of households responding to the daily text declined after enrollment, and only 30% (26/87) responded through the end of the monitoring period. Of the 187 survey respondents, 21 (11%) participated in TIM. Of those, 80% (16/20) participated because it was recommended by the fair and 79% (15/19) said they would participate again. Of those who did not participate, and gave a reason, 74% (99/134) said it was because they had not heard about it and 12% (16/134) said they did not understand the necessity. Through the interviews, local health departments reported that TIM reduced their workload, but state and federal health departments reported additional workload to initiate and coordinate TIM.
CONCLUSIONS: A pilot text-based monitoring system was implemented during an ongoing outbreak and successfully identified two of the 12 H3N2v virus infections identified in Michigan. Challenges, including enrollment, sustaining participation, and systematic testing of ill respondents, were identified, and improvements in these areas will make future deployments of TIM more successful.