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EPIDEMIOLOGY, PREVENTION
AND PUBLIC HEALTH - TRACK C
Summary of Tuesday, 30 June, 1998

Introduction
Three epidemic trends can be observed :

• Explosive epidemics;
• Masked epidemics;
• Emerging epidemics.

Explosive epidemic
Characteristics of explosive epidemics :

• Late introduction of HIV;
• Rapid growth and;
• High case-load.

High incidence in young people, including vulnerable women and geographic mobility, are factors which fuel the epidemic.

• The objective of one intervention for vulnerable people was to provide support for women whose male partners also had sex with other men. This included reaching-out to the women through a variety of media (articles, newspapers, radio and television messages and advertisements).

• Other interventions were developed at the community level, in particular appropriate interventions for low income vulnerable women. One programme had three components :

1. Women’s health council (include peer opinion leaders);
2. Skills training workshops (over 2 weeks, aimed to build communication, self efficacy), which the peer leaders underwent first;
3. Community Activities and Events (play, carnival, health fair, videos).

Community intervention models can change risk behaviours. Interventions have to be targeted and tailored. Collaboration is necessary for development, implementation and continuation. Key opinion leaders can mobilise community based HIV prevention efforts.

• Migration not only has been an important cause for starting the HIV pandemic, it continues to fuel it. Several sessions have dealt with this vast topic. Reasons for the enormous changes are numerous but fall under the headings of ‘Push’ and ‘Pull’.

• Examples of ‘push’ includes war, famine and other natural disasters. One presentation focused on the recent events in Bosnia and Herzegovina and referred to the very high level of sexual violence and rape. Similar evidence is emerging from other continents including Central and Southern Africa.
• Examples of ‘Pull’ included male labour migrants in India. In China, there are one hundred and twenty million migrants seeking for better working and living conditions every year.
• Different migrant populations present different aspects of vulnerability. Factors operated at both individual and social levels.

At the individual level : inadequate STD treatment, lack of information and education, lack of access to HIV screening, inadequate access to condoms, unscreened blood transfusions, lack of sterile injection equipment, inadequate diagnostic facilities, sexual exploitation of women refugees.

At the social level, major factors proposed as contributing to the transmission of HIV:

1) deprived living conditions;

2) disruption of social support;

3) dysfunctional social organisation.

• Given the recent African experience, it is very disappointing to see the same mistakes being made in other regions of the world.

Any research and intervention programs need to focus on the conditions :

1. In the country left by the migrants;
2. During the process of migration itself;
3. The country of destination.

Masked epidemics

• Stable prevalence rates are a characteristic of masked epidemic but different sub-populations may have different incidence rates. High incidence rates may be masked by high mortality rates. In some countries, mortality rates are coming down.
• The treatment impact of combination anti-retroviral therapy or HAART is now being reported from many countries. Apart from the fact that many under privileged groups in industrialised countries have limited access to these treatments, current social and economic conditions in many developing countries restrict these treatments to the privileged few.
• The increased availability of anti-retroviral therapy, has highlighted the issue of post exposure prophylaxis (PEP). As for occupational exposures, standard regimen now include (Highly antiretroviral therapy active (HAART) or double nucleoside reverse transcriptase inhibitors (NRTIs). The majority of those taking PEP present minor reversible side effects but data are inconsistent regarding their contribution to the premature cessation of treatment in many health care workers. Follow-up for exposed health care workers is still far from optimal. PEP for non-occupational exposures is now a reality in many countries and different protocols have been developed and implemented. Data are still quite scarce but according to available studies having addressed mostly process evaluation, adherence to treatment, capacity to know the HIV status of the source of exposure and compliance to follow-up may vary according to different characteristics such as the type of population presenting for PEP and the type of exposure (assault versus consensual exposure).

Emerging epidemics

• Key characteristics include overall low prevalence but increasing incidence rates in sub-group or regions. There is a potential for rapid spread into other sub-groups but the evolution of the epidemic remains uncertain.

• This requires careful monitoring of the general population and high risk groups. We need to understand the causes of the spread of HIV in these sub-groups and how they can be reached both for treatment and prevention. Such groups include commercial sex-workers and their clients while much work is performed with commercial sex-workers, their clients are often forgotten. Intervention programs can also be peer-based.

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