Epidemiological surveillance of HIV infection AIDS in Europe

1. Epidemiological surveillance of HIV infection & AIDS in Europe Advanced course in epidemiology of infectious diseases EpiTrain II - Tallinn, Estonia, 7 September 2005 I am an epidemiologist working for Euro HIV I am going to present methodological issues related to epidemiological surveillance os HIV infection and AIDS in Europe. I am an epidemiologist working for Euro HIV I am going to present methodological issues related to epidemiological surveillance os HIV infection and AIDS in Europe.

2. HIV/AIDS surveillance in Europe: EuroHIV Started in 1984 Covers 52 countries of the WHO EURO Region WHO and UNAIDS Collaborating Centre Formerly, the European Centre for the Epidemiological Monitoring of AIDS - transferred to InVS in 1999 EU funded EuroHIV is a EU funded program that co-ordinates the surveillance of HIV/AIDS in the WHO European Region (52 countries) since 1984�EuroHIV is a EU funded program that co-ordinates the surveillance of HIV/AIDS in the WHO European Region (52 countries) since 1984�

3. Presentation outline Second generation HIV surveillance Review of the epidemiological methods used to monitor the HIV epidemic in Europe Case reporting HIV prevalence Description of recent epidemiological trends Example of a national HIV surveillance system Norway (P. Aavitsland)

4. A global view of HIV infection 39.4 million people [range: 35.9-44.3 million] living with HIV at end 2004 The number of people living with HIV infection in 2004 is estimated to be 39 million. The countries with the higest prevalence are located in Africa. Prevalnce is also high in some parts of Europe.The number of people living with HIV infection in 2004 is estimated to be 39 million. The countries with the higest prevalence are located in Africa. Prevalnce is also high in some parts of Europe.

5. The countries are classified according 3 different epidemic states�The countries are classified according 3 different epidemic states�

6. 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, homosexual men. 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. In low level epidemics we cannot find HIV prevalence above 5% in any population group.Either the virus has been recently introduced or the determinants of the epidemics are not present enough to sustain a rapid spread of the virus. Risk assessment can help us guess whether the epidemic will progress or stay the same.In low level epidemics we cannot find HIV prevalence above 5% in any population group.Either the virus has been recently introduced or the determinants of the epidemics are not present enough to sustain a rapid spread of the virus. Risk assessment can help us guess whether the epidemic will progress or stay the same.

7. 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. Several countries are in a concentrated epidemic state. In this case, HIV prevalence is above 5% in some HRG but still well below 1% in the general population represented by pregnant women in urban areas. Again,. STI and behavioural surveillance will help predict whether the epidemic will become generalised or remain concentrated in these high-risk groups.Several countries are in a concentrated epidemic state. In this case, HIV prevalence is above 5% in some HRG but still well below 1% in the general population represented by pregnant women in urban areas. Again,. STI and behavioural surveillance will help predict whether the epidemic will become generalised or remain concentrated in these high-risk groups.

8. 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. Countries are considered to have a generalized HIV epidemic with HIV prevalence above 1% in the general population. The extent and intensity of risk behaviours facilitating HIV sexual transmission will determine the future of the epidemic. Countries are considered to have a generalized HIV epidemic with HIV prevalence above 1% in the general population. The extent and intensity of risk behaviours facilitating HIV sexual transmission will determine the future of the epidemic.

12. Indicators for HIV/AIDS surveillance HIV Counselling: Confidential dialogue between a client and a care provider aimed at enabling the client to cope with stress and take personal decisions related to HIV/AIDS. Voluntary Counselling and Testing: Is combination of two activities counselling and testing � into a service that amplifies the benefits of both HIV Counselling: Confidential dialogue between a client and a care provider aimed at enabling the client to cope with stress and take personal decisions related to HIV/AIDS. Voluntary Counselling and Testing: Is combination of two activities counselling and testing � into a service that amplifies the benefits of both

13. Data collection methods for HIV surveillance Biological surveillance HIV / AIDS case reporting issues: AIDS case definition & important role in advocacy integration in the communicable disease reporting system Prevalence surveys � Sentinel serosurveillance in defined sub-populations � Regular HIV screening of donated blood / occupational cohorts or other sub-populations � HIV screening of specimens taken in general population surveys or special population surveys

14. Indicators for HIV/AIDS surveillance HIV Counselling: Confidential dialogue between a client and a care provider aimed at enabling the client to cope with stress and take personal decisions related to HIV/AIDS. Voluntary Counselling and Testing: Is combination of two activities counselling and testing � into a service that amplifies the benefits of both HIV Counselling: Confidential dialogue between a client and a care provider aimed at enabling the client to cope with stress and take personal decisions related to HIV/AIDS. Voluntary Counselling and Testing: Is combination of two activities counselling and testing � into a service that amplifies the benefits of both

15. Data collection methods for HIV surveillance Behavioural surveillance General population-based behavioural surveys ? most appropriate tool for tracking changes in exposure to risk of HIV infection in the general population over time Ex. telephone surveys on sexual behaviour Sub-population-based behavioural surveys MSM IDU Sex workers

16. Indicators for HIV/AIDS surveillance HIV Counselling: Confidential dialogue between a client and a care provider aimed at enabling the client to cope with stress and take personal decisions related to HIV/AIDS. Voluntary Counselling and Testing: Is combination of two activities counselling and testing � into a service that amplifies the benefits of both HIV Counselling: Confidential dialogue between a client and a care provider aimed at enabling the client to cope with stress and take personal decisions related to HIV/AIDS. Voluntary Counselling and Testing: Is combination of two activities counselling and testing � into a service that amplifies the benefits of both

17. Data collection methods for HIV surveillance Other sources of information Death registration STI indicators & other biological markers of risk

18. Major indicators used in HIV surveillance 1. Biological indicators � Estimation of HIV prevalence � Number of adult/paediatric AIDS cases 2. Behavioural indicators � Sex with a non-regular partner in the last 12 months � Condom use at last sex with a non-regular partner � Youth: age at first sex � Drug injectors: Reported sharing of unclean injecting equipment � Sex workers: Reported number of clients in the last week 3. Socio-demographic indicators Age, sex, socioeconomic & educational status, indicator of residency or migration status, parity, marital status

19. Presentation outline Second generation HIV surveillance Review of the epidemiological methods used to monitor the HIV epidemic in Europe Case reporting HIV prevalence Description of recent epidemiological trends Example of national HIV surveillance system Norway (P. Aavitsland)

20. European AIDS and HIV case reporting AIDS case reporting Since 1984 (all countries) HIV case reporting Implemented at national level since late 1980s in most countries (not yet implemented in Italy and Spain) Since 1999 at European level

21. HIV / AIDS reporting Definition of confidentiality, anonymity Confidential: told in confidence; imparted in secret (Webster dictionary) Anonymous: with no name known or acknowledged (Webster) Personal identifying information at national level Name Social security number Other: genetic code, finger print, photograph, ancillary data (age & sex) may be identifying in small areas, etc. No identifier at European level

22. HIV / AIDS reporting Definitions (cont.) Anonymous unique identifier Reproducible: the same individual must always have the same identifier Unique: no two individuals must have the same identifier

23. HIV / AIDS Case reporting AIDS Case definition 1993 European AIDS surveillance case definition One of the 28 specified opportunistic illnesses (OI) Positive test for HIV infection Does not include CD4 count <200/?L without OI

24. HIV / AIDS Case reportingList of AIDS indicator diseases

25. HIV / AIDS Case reporting Data collection & management

26. HIV / AIDS Case reportingDatabases Databases of anonymous and individual data reported every 6 months: ENAADS: European Non-Aggregate AIDS Data Set (52 countries, started in 1990) EHIDS: European HIV Infection Data Set (33 countries, started in 1999) Database on aggregate data on new HIV cases (countries without individual datasets ) Ideally we want to have one single database with each case reported at 3 different points in time. Because not all countries are able to link HIV and AIDS reports (which is a problem!) we are obliged at the European level to maintain 2 databases (1 for HIV and 1 for AIDS). Also, all countries should be able to provide individual cases; unfortunately, some don't. This is a problem. It means that data cannot really be checked for validly and unconsistancies, it also mean that the analyses we can make is extremely basic. We should really be aiming at having all countries providing individual data. Ideally we want to have one single database with each case reported at 3 different points in time. Because not all countries are able to link HIV and AIDS reports (which is a problem!) we are obliged at the European level to maintain 2 databases (1 for HIV and 1 for AIDS). Also, all countries should be able to provide individual cases; unfortunately, some don't. This is a problem. It means that data cannot really be checked for validly and unconsistancies, it also mean that the analyses we can make is extremely basic. We should really be aiming at having all countries providing individual data.

27. HIV/AIDS Case reportingEHIDS data file specification (1) CASENO: Case number given by the country COUNTRY: Country of report SEX: 1 = male, 2 = female, 9 = unknown BIRTHYR: Year of birth HIVYR: Year of HIV diagnosis HIVQR: Quarter of HIV diagnosis REPYR: Year of report REPQR: Quarter of report HIV_TYPE: Type of virus STAGE: Clinical stage at time of HIV diagnosis

28. HIV/AIDS Case reportingEHIDS data file specification (2) TRM_CAT: Transmission category TRM_HET: Transmission sub-category of heterosexual contact cases TRM_MOTH: Mother's transmission category PREVPOS: Positive HIV test >1 year prior to the test being reported INFECTYR: Probable year of infection with HIV AIDSYR: Year of AIDS diagnosis AIDSQR: Quarter of AIDS diagnosis DEATHYR: Year of death DEATHQR: Quarter of death ORIGIN: Country or subcontinent of origin

29. HIV/AIDS Case reportingTransmission groups Homo/bisexual male Injecting drug user Haemophiliac Transfusion recipient Heterosexual contact Country with a generalized HIV epidemic High risk partner (HBM, IDU, haemophiliac, transfusion recipient�) Partner from a country with a generalized epidemic Mother-to-child transmission Nosocomial infection

31. HIV/AIDS Case reportingAggregate data (2)

33. Presentation outline Second generation HIV surveillance Review of the epidemiological methods used to monitor the HIV epidemic in Europe Case reporting HIV prevalence Description of recent epidemiological trends Example of national HIV surveillance system Norway (P. Aavitsland)

34. HIV prevalenceSentinel serosurveillance (1)

35. HIV prevalenceSentinel serosurveillance (2) Populations regularly screened for HIV infection Donated blood units or blood donors Occupational cohorts factory workers migrant workers military

36. HIV prevalenceCross-sectional serosurveys in sub-populations at risk Attempts to get around selection bias associated with sentinel surveillance Sampling usually household-based Requires informed consent

38. European HIV Prevalence Database

40. Presentation outline Second generation HIV surveillance Review of the epidemiological methods used to monitor the HIV epidemic in Europe Case reporting HIV prevalence Description of recent epidemiological trends Example of national HIV surveillance system Norway (P. Aavitsland)

42. Description of recent epidemiological trends HIV infections AIDS cases

67. Prevalence data