5  Infection Event (Stage 2)

Choosing the right event is crucial and depends on the objectives

Surveillance systems monitor a wide range of infection-related events. Understanding the event is essential for understanding a surveillance system.The choice of events to monitor in a surveillance system is a critical decision that shapes the system’s in many ways. The choice depends on the Objective of the surveillance system.

• If a case-based intervention is intended the event that is monitored should be able to provide contact information of a case
• If only goup-based intervention is inteded only a trend is needed which can be acquired by simpler systems
• When the objective of a surveillance system is to monitor hospital capacity for resource allocation decisions, the events tracked should focus on specific indicators of hospital capacity and utilization like bed occupancy of staff coverage.

5.1 Naming and Categorization

Surveillance systems are often named after the events they monitor. For example:

• Emergency department surveillance (Emergency department visits)
• Syndromic surveillance (based on monitoring syndromes)
• Lab-based surveillance system (Reports by labs)
• Meidasurveillance (Screening of media articles)

5.2 Typical events in infectious disease surveillance

• The occurence of an infectious disease
• The occurence of an infection (infected person who is not necessarily diseased)
• An available ICU bed
• Self reports by people that they fell sick
• The colonization of a person by a pathogen
• A physician’s ICD-10 classification of a patient
• The discovery of a newspaper article about a disease outbreak
• The subjective assessment of a public health department employee that something poses a threat to the population.
• A social media signal detected by a software