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

Programmes may need to be updated based on new information about the epidemic. As you process
feedback (findings/data) from the last round of surveillance activities, your data priorities may need to shift.
An example can be provided by data analysis of the Honduras HIV epidemic (Figure 4.8). The HIV notification
rates per 100 000 population are higher in the coastal regions compared with the rest of the country. At the
same time, the male-to-female (M:F) ratio of people infected with HIV in the north is close to 1, whereas in
the rest of the country the M:F ratio is 3:1. This characteristic has been constant over time, which implies
that two different epidemics are evolving in the country.
4.3.3. Indentify where new infections are occurring
Epidemiological information can contribute to indentifying where new infections are coming from. For
instance, this information is key to using the UNAIDS Modes of Transmission model (MOT). It uses national
prevalence and behavioural data to model the distribution of incidence in key populations at increased risk. It
is therefore an important tool in supporting country programmes to “Know the HIV Epidemic” and therefore
modify programmes. The epidemiological synthesis preceding the modelling exercise is a key requirement
for developing a clear explanation of the dynamics of HIV infection, assessing the degree of alignment
between programme and resource efforts, and the priority areas identified through the modelling exercise.
By developing an understanding of the national epidemic and context (gaps, risks, service coverage and
resources), the country is able to make better decisions on prioritization and definition of goals and targets
for effective scale up of the national response.
As an example, Figure 4.9 presents the results of the Modes of Transmission study in selected African
countries and where it was evident that key populations at higher risk played a major role in transmission
of new HIV infections.
Figure 4.8. Taux de cas d’infection à VIH notifiés pour 100 000 habitants, stratifiés par situation
géographique et par sexe, Honduras, 1997–2009
Tasa por 100,000 habitantes
70.0
60.0
50.0
40.0
30.0
20.0
10.0
CN (1,2,5,11) - Mujer
Resto - Mujer
CN(1,2,5,11) - Hombre
Resto - Hombre
0.0
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Año
CN: North Coast H: men and M: women
Resto: rest of the country, mujer: women, hombre: men
Source : Honduras National AIDS Programme: triangulation of national data, 2011.
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