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UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Introduction to 2nd Generation HIV Surveillance UNAIDS/WHO Working Group on Global HIV/AIDS.

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Presentation on theme: "UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Introduction to 2nd Generation HIV Surveillance UNAIDS/WHO Working Group on Global HIV/AIDS."— Presentation transcript:

1 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Introduction to 2nd Generation HIV Surveillance UNAIDS/WHO Working Group on Global HIV/AIDS and STI Surveillance

2 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Public Health Surveillance of HIV The collection, analysis and dissemination of epidemiological information of sufficient accuracy and completeness regarding the distribution and spread of HIV infection to be relevant to the planning, implementation and monitoring of HIV/AIDS prevention and control programmes.

3 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance HIV/AIDS: Data Needs What are the levels and trends in HIV infection? Who is getting infected? Who is at risk for or vulnerable to HIV infection? What is the impact of the epidemic? Is the response effective?

4 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Use of STI/HIV surveillance data Situation analysis Strengthen commitment Resource mobilization Targeting interventions Planning and evaluation of intervention Programme assessment and evaluation

5 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Is HIV surveillance special? Unique epidemiology (multiple epidemics) Wide variation in prevalence No definite cure yet Very long asymptomatic (latency) period Severity of AIDS Severe personal and social implications of identifying HIV-infected persons

6 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance A global view of HIV infection 33 million adults living with HIV/AIDS as of end 1999 Adult prevalence rate 15.0% – 36.0% 5.0% – 15.0% 1.0% – 5.0% 0.5% – 1.0% 0.1% – 0.5% 0.0% – 0.1% not available

7 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance

8 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance UNAIDS/WHO Classification of epidemic states LOW LEVEL: HIV prevalence has not consistently exceeded five percent in any defined sub-population CONCENTRATED HIV prevalence consistently over five percent in at least one defined sub-population but below one percent in pregnant women in urban areas. GENERALISED HIV prevalence consistently over one percent in pregnant women nation-wide

9 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance LOW LEVEL Principle: Although HIV infection may have existed for many years, it has never spread to significant levels in any sub-population. Infection is largely confined to individuals with higher risk behaviour: e.g. sex workers, drug injectors, MSM. This suggests that networks of risk are rather diffuse (low levels of partner exchange or sharing of drug injecting equipment), or a very recent introduction of the virus. Numerical proxy: HIV prevalence has not consistently exceeded five percent in any defined sub-population.

10 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance CONCENTRATED Principle: HIV has spread rapidly in a defined sub-population, but is not well-established in the general population. This suggests active networks of risk within the sub-population. The future course of the epidemic is determined by the frequency and nature of links between highly infected sub- populations and the general population. Numerical proxy: HIV prevalence consistently over five percent in at least one defined sub- population. HIV prevalence below one percent in pregnant women in urban areas

11 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance GENERALISED Principle: In generalised epidemics, HIV is firmly established in the general population. Although sub-populations at high risk may continue to contribute disproportionately to the spread of HIV, sexual networking in the general population is sufficient to sustain an epidemic independent of sub-populations at higher risk of infection. Numerical proxy: HIV prevalence consistently over one percent in pregnant women nation- wide.

12 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance LESSONS LEARNED from HIV surveillance Strengths Relatively simple and cheap Increase awareness and raise commitment Generating response Target activities Monitor success Weaknesses No risk behaviours Poor early warning Little use of other sources of data One size fits all Not suitable for slow or mature epidemics It is difficult to derive HIV prevalence estimates

13 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance 2nd generation HIV surveillance It is not new or different but improved Builds on the lessons learnt in the first decade of surveillance for HIV Attempts to capture the diversity of the HIV epidemics in different areas Considers the state of the epidemic low-level concentrated generalised Integrates biological surveillance (AIDS, HIV) with RISK surveillance (behaviours, STI) Looks at new methodologies and improved ways for using HIV epidemiological data

14 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance 2nd generation HIV surveillance AIDS reporting HIV surveillance STI surveillance behavioural surveillance Data management HIV estimates and projections Use of data for action Data analysis

15 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance WINDOW PERIOD INFECTION ASYMPTOMATIC PERIOD HIV ILLNESS or AIDS DEATH RISK SURVEILLANCE HIV INCIDENCE SURVEILLANCE HIV PREVALENCE SURVEILLANCE AIDS CASE SURVEILLANCE AIDS DEATHS = VIRAL LOAD= HIV ANTIBODIES

16 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Courtesy of Dr. Thomas Rehle, Family Health International

17 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Data collection methods Biological surveillance Sentinel sero surveillance in defined sub-populations Regular HIV screening of donated blood Eventual regular HIV screening of other sub-populations HIV screening of specimens taken in population surveys Behavioural surveillance Repeat cross-sectional surveys in the general population Repeat cross-sectional surveys in defined sub-populations Other sources of information HIV and AIDS case surveillance Death registration STD surveillance, TB surveillance, Hepatitis surveillance

18 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Key questions for low-level and concentrated epidemics: a summary Is there any risk behaviour that might lead to an HIV epidemic? In which sub-populations is that behaviour concentrated? What is the size of those sub-populations? How much HIV is there in those sub-populations? Which behaviours expose people to HIV in those sub- populations and how common are they? What are the links between sub-populations at risk and the general population?

19 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Surveillance in low-level epidemics Cross-sectional surveys of behaviour in sub-populations with risk behaviour Surveillance of STDs and other biological markers of risk HIV surveillance in sub-populations at risk HIV and AIDS case reporting Tracking of HIV in donated blood

20 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Surveillance in concentrated epidemics HIV and STI/behavioural surveillance in sub-populations with risk behaviour HIV and behavioural surveillance in bridging groups Cross-sectional surveys of behaviour in the general population HIV sentinel surveillance in the general population, urban areas

21 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Key questions for surveillance in a generalised epidemic What are the trends in HIV infection? To what extent do trends in behaviour explain trends in prevalence? Which behaviours have changed following interventions and which continue to drive the epidemic? What impact is the epidemic likely to have on individual, family and national needs?

22 UNAIDS/WHO Working Group on Global HIV/AIDS/STI Surveillance Surveillance in generalised epidemics Sentinel HIV surveillance among pregnant women, urban and rural Cross-sectional surveys of behaviour in the general population Cross-sectional surveys of behaviour among young people HIV and behavioural surveillance in sub- populations with high risk behaviour Data on morbidity and mortality

23 Jun-89 Dec-89 Jun-90 Dec-90 Jun-91 Dec-91 Jun-92 Dec-92 Jun-93 Dec-93 Jun-94 Dec-94 Jun-95 Dec-95 Jun-96Jun-97Jun-98Jun-99 HIV Prevalence Among Pregnant Women, Male Conscripts, and Donated Blood Thailand % Month/Year Pregnant women Donated blood Source: Sentinel Serosurveillance, Division of Epidemiology, Ministry of Public Health. Remark: Switching from bi-annually (June and December) to annually in June since 1995 Conscript data in November of each year since 1995 were not shown here Conscripts (age 21)

24 Clients Using Condoms and STI Cases Reported - Thailand Clients using condom STI cases reported STI cases reported ( thousands) % using condoms Source: Sentinel Serosurveillance, Division of Epidemiology, Ministry of Public Health.


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