Epidemiological surveillance of HIV/AIDS

Epidemiological surveillance

Epidemiological surveillance is the monitoring of the occurrence of disease in the population.  In particular this should show how this varies with time, by place and among different groups in the population. 

A more formal definition is “ongoing, and systematic collection, analysis and interpretation of outcome-specific heath data for use in the planning, implementation and evaluation of public health practices”. 

Epidemiological surveillance is an ongoing process as shown in the Figure below.

UNAIDS/WHO recommendation for HIV/AIDS surveillance

UNAIDS/WHO have developed a framework for HIV/AIDS surveillance (“Second generation surveillance”) that recognises the need not just to monitor cases of AIDS and identified HIV infection, but also the behaviours that drive the epidemic. This framework also identifies the need to monitor systems of different intensity depending on the level of the epidemic.

The HIV/AIDS epidemic in New Zealand meets the UNAIDS/WHO criteria for a “low-level” epidemic as infection is largely confined to individuals with higher risk behaviour, particularly men who have sex with men (MSM) and HIV prevalence has not consistently exceeded five percent in any defined sub-population.

Surveillance in countries with a low-level epidemic needs to focus largely on high-risk groups and behaviours, looking for changes in behaviour which may foster a rapid spread of infection.

Surveillance of HIV/AIDS in New Zealand

The recommendation for surveillance in countries, such as New Zealand, that have a “low-level” of HIV is for:

• AIDS and HIV case reporting
• HIV surveillance in sub-populations at risk
• Cross-sectional surveys of behaviour in sub-populations with risk behaviour
• Surveillance of sexually transmitted infections (STIs) and other biological markers of risk
• Tracking of HIV in donated blood

The activities of the AIDS Epidemiology Group therefore follow these guidelines and are outlined on the Activities page.