Incidence for selected diseases relevant to the local context

Useful measure of the burden of diseases and detect outbreaks. The list of diseases is context specific and can include communicable and non-communicable diseases.

Numerator

Number of cases of selected disease in a defined administrative or health area in a given period of time

Denominator

Total population in the same administrative or health area and at the same time period

Disaggregation

Administrative area; health area; age (usually < 5 years; >= 5 years)

Indicator used for response monitoring ?

Yes

Types

Baseline

Threshold / Standard

Thresholds for alert/outbreak depending on disease Follow-up of trends

General guidance

Calculation: incidence rate, i.e. number of cases per pers per time period, should be calculated, especially when large population movement occurs; however, in many settings, accurate calculation of incidence is severely limited by inaccurate population data, and total number of cases seen should be used instead. Proportional morbidity (cases of disease divided by total cases and expressed as a percentage) is also useful when the population denominators are unknown or changing. Interpretation: can be used both for detection of outbreaks and for monitoring of the effect of the health response. Limitations: Health facility surveillance may have low sensitivity for conditions that do not commonly go to clinic. Access to health services is another factor.

Guidance on phases

There is a differing level of quality of data which can be collected at different phases of the emergency depending on the context, eg the data available and the systems for data collection in place before the crisis, the accessibility of the affected areas, the resources on the ground, etc...

Phase applicability

Pre-crisis/Baseline

Phase 1

Phase 2

Phase 3

Phase 4

Data Sources

Numerator: EWARS, health facility based surveillance, routine health facility reporting system Denominator: administrative boundaries; health areas boundaries; population per administrative area; population per health areas;

Comments

Further guidance: Outbreak surveillance and response in humanitarian emergencies (http://whqlibdoc.who.int/hq/2012/WHO_HSE_GAR_DCE_2012_1_eng.pdf)