Syndromic surveillance

Why it matters

Laboratory confirmation takes time, and many facilities have limited access to it. Syndromic surveillance trades diagnostic precision for speed: it can show that something unusual is happening while confirmation is still pending. WHO describes early warning systems in emergencies as usually syndromic, with each condition identified by a case definition and an alert triggered when a set threshold is crossed [1].

Key points

• The Pacific Syndromic Surveillance System, established in 2010, covers 23 Pacific Island countries with weekly reporting. For most syndromes an alert fires at twice the recent average; for acute fever and rash, severe acute respiratory infection and COVID 19 a single case is enough [2].
• An early study of seven emergency departments in southeastern Virginia found that syndromic data showed the start of the 2002 influenza season about nine days ahead of the sentinel system [3].
• The same study found that manual categorisation and transfer by fax delayed detection [3]. Coding at source and automated classification remove that delay.
• Syndromic counts are signals for investigation, not diagnoses.

In Moana

MOANA Surveillance classifies encounters by syndrome as they are recorded and applies alert thresholds, so increases appear on national dashboards without a separate count.

Sources

1. Early Warning, Alert and Response Network (EWARN), WHO Regional Office for the Eastern Mediterranean, accessed 2026
2. Pacific Syndromic Surveillance System, Pacific Public Health Surveillance Network, accessed 2026
3. Syndromic Surveillance at Hospital Emergency Departments, Southeastern Virginia, Morbidity and Mortality Weekly Report, US CDC (Yuan, Love, Wilson), 2004