Figure 1. Time Series From Participatory Surveillance Data and Viral Case Rates From Publicly Available Data Sources.

Vertical lines define the beginning of each pandemic period. US COVID-19 case counts in panel D are sourced from the Johns Hopkins University Center for Systems Science and Engineering,²² the number of positive influenza cases from clinical laboratories using FluView Interactive,¹⁴ and the number of positive respiratory syncytial virus (RSV) cases from clinical laboratories in the National Respiratory and Enteric Virus Surveillance System (NREVSS).¹⁵