Methods: Randomized households were provided with a smartphone and asked to submit weekly reports using a symptom diary Application (Vigilant-e). Subjects reporting AFI or AGE answered additional questions using a decision-tree algorithm and were visited at home by a study nurse who performed a second interview and collected samples for DENV (AFI) and NoV (AGE). We analyzed risk factors associated with decreased self-reporting of syndromic data and evaluated strategies to improve self-reporting. We also assessed agreement between self-report and nurse-collected data.
Results: From 4/2015-6/2016, 469 children in 207 households provided 471 person-years of observation. Mean weekly symptom reporting rate was 78% (range: 58-89%). Households with a poor (<70%) reporting rate using the Vigilant-e application (n=57) had a greater number of children (mean=2.8 vs 2.5, risk ratio [RR]=1.2, 95%CI=1.1-1.4) and were less likely to use text messaging at study enrollment (61% vs 77%, RR=0.6, 95%CI=0.4-0.9). Parents of female subjects were more likely to have low response rate (57% vs 44%, RR=1.4, 95%CI=1.1-1.9). Poor response rate (<70%) was associated with decreased case reporting of AGE, NoV+ AGE, AFI, and DENV+ AFI (p<0.001). Parent smartphone-reported syndromic data agreed with nurse-collected data for fever (kappa=0.57, p<0.001), vomiting (0.63, p< 0.001), and diarrhea (0.61, p<0.001), with decreased agreement as the time interval between parental report and nurse home visit increased (<1 day kappa: 0.65-0.70; >2 day kappa: 0.08-0.29).
Conclusion: In a resource-limited area of rural Guatemala, a smartphone application-based participatory syndromic surveillance system demonstrated a high reporting rate and good agreement between parental report and nurse report during home visits. Several household-level and external factors were associated with decreased syndromic reporting. Poor reporting rate was associated with decreased syndromic and pathogen-specific case ascertainment.
M. R. Lopez, None
K. Colborn, None
A. Paniagua-Avila, None
A. Zacarias, None
R. Zambrano, Integra IT: Employee and Shareholder , Salary
S. Rodriguez-Castro, Integra IT: Employee and Shareholder , Salary
C. Cordon-Rosales, None
E. J. Asturias, Takeda Pharmaceuticals: Consultant and Grant Investigator , Grant recipient