Guidelines for second generation HIV surveillance - World Health ...

• Data from interventions or programmatic data
• Secondary data sources (from non-health sector).
No one source of surveillance data will answer all questions. One must pull data together, then triangulate
(or synthesize) the data and interpret the results (7).
2.1.2. Know your epidemic
As recent national and regional/local information is reviewed, the information needed to know your epidemic
will begin to emerge (1). Knowing a country’s epidemic consists of identifying the important epidemiological
regions where new infections are coming from and understanding how the epidemic is changing, either due
to natural causes or as a result of interventions.
Evaluating a National Surveillance System
To provide information for data-driven planning for HIV programmes, one needs:
• to identify parts of the country where the epidemic appears to be the most severe;
• to describe the different factors that seem to be promoting new infections in different parts of the country;
• to list areas where there are few infections and possibly little transmission;
• to distinguish between areas with few infections and areas where there is no information;
• to describe which systems are already in place to detect areas with emerging epidemics and assess how
sensitive these systems are.
2.1.3. Learn where most new infections come from in your country
There are two dimensions one must know in order to understand where most new infections are occurring.
These are the geography of the country and the various behaviours that put people at increased risk for HIV
infection. It is important to know the context in which HIV transmission occurs.
The geography → First dimension: the geography
Most countries have diverse regions with varying socioeconomic conditions and populations. An effective
surveillance system must describe what is happening in every geographical region across the country or
at least where the majority of the people live. In this way, one can provide information to planners of
intervention programmes.
Behaviours at increased risk → Second dimension: behaviours at increased risk
Some behaviours are likely to result in more infections in some parts of a country and among some
people. A country must identify the key populations with behaviours that increase their risk for acquiring or
transmitting HIV. Some behaviours that increase a person’s risk to HIV are:
• heterosexual sex with multiple and overlapping partners
• selling of sex
• injection drug use
• anal sex.
Identify data sources that provide information on these risk behaviours from surveys or programme records,
from police records or other possible data sources. Alternatively, identify sources of data on populations
that often engage in these behaviours such as truck drivers or prisoners. Risk behaviours and their context
are discussed further in section 2.2.
2.1.4. Develop a surveillance inventory
A surveillance inventory is a summary of the data sources that are available for the key populations in each
geographical unit of a country. A surveillance inventory provides surveillance managers with an overview
of where data may be insufficient to “know your epidemic”.
Choose geographical units
The units should reflect how data are collected and how the response is organized. At this early stage, one
can use administrative divisions like districts, for example, aligned with the boundaries used for routine
health information data collection, programme budgets or management structures. One way to organize the
information currently available for each geographical unit is to create an inventory of surveillance activities.
Begin the inventory by listing each geographical unit as, for instance, in Table 2.1, left column. Later, one can
add what data sources are available for each key population at higher risk, as given in section 2.2.
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