Abstract
To assess the timeliness of detection, formal notification and completion of applicable early response actions for priority public health events in Sierra Leone, and to identify documented operational constraints in delayed events and enabling process features in timely events. Retrospective observational event-level study. We analysed all 33 verified priority public health events recorded in the national Situation Room register from 1 February 2023 to 31 January 2025. Using a prespecified protocol adapted from World Health Organization Early Action Review and 7-1-7 Alliance tools, two reviewers reconstructed four milestone dates from dated surveillance, response, laboratory and specimen-transport records. We summarised target attainment, interval distributions and the post-notification share of total elapsed time. Reviewers coded documented constraints in 22 delayed events and conducted a positive-case review of affirmative enabling features in 11 timely events. Detection, notification and early-response targets were met in 22/33 (66.7%), 25/33 (75.8%) and 11/33 (33.3%) events, respectively; 11/33 (33.3%) met all three targets. Median emergence-to-detection, detection-to-notification and notification-to-completion intervals were 5 days (interquartile range [IQR] 3-9; range 1-21), 1 day (IQR 0-1; range 0-4) and 17 days (IQR 7-35; range 3-74). The median event-level proportion of total elapsed time occurring after notification was 73.5%. Delayed events commonly documented financing, logistics, specimen, laboratory and deployment constraints. Timely events showed prompt escalation, district-led initiation, ready transport and diagnostic pathways, available initial supplies, early coordination and familiar procedures. Only one-third of registered events met all three 7-1-7 targets. Most elapsed time occurred after formal notification, when recognised threats needed to be converted into completed early response actions. Improvement should remove mobilisation constraints while preserving and standardising the enabling practices observed in timely events.