Fig. 2
From: Design of effective outpatient sentinel surveillance for COVID-19 decision-making: a modeling study
Example trajectories of COVID-19 indicators and their derived Rt, from a single, representative simulation with a population of 2.5Â million, moderate transmission hike, and alarm triggered by hospital occupancy. (A) Indicators are steady before and rise rapidly after the transmission hike. Arrows: peak for each indicator. Vertical dashed line: day of transmission hike. (B) Rt estimated based on each indicator, evaluated on day 60 after the transmission hike. Rt could not be estimated using hospital occupancy. Horizontal dotted line: threshold (Rt=1.05) for triggering the alarm. Arrows: day alarm would have been triggered based on monitoring Rt for each indicator. (C) Real-time evaluation of Rt demonstrates the operational recency advantage of sentinel surveillance over hospital admissions. Example shown for evaluation day of 20 days after the transmission hike