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Epidemiological surveillance of HIV infection & AIDS in Europe
Advanced course in epidemiology of infectious diseases
EpiTrain II - Tallinn, Estonia, 7 September 2005
EuroHIVDepartment of Infectious DiseasesInstitut de Veille Sanitaire (InVS)
HIV/AIDS surveillance in Europe: EuroHIVStarted 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
Integration of HIV/AIDS surveillance in European CDC to be defined
Presentation outline
1. Second generation HIV surveillance
2. Review of the epidemiological methods used to monitor the HIV epidemic in Europe• Case reporting• HIV prevalence
3. Description of recent epidemiological trends
4. Example of a national HIV surveillance system
Norway (P. Aavitsland)
A global view of HIV infection 39.4 million people [range: 35.9-44.3 million]
living with HIV at end 2004
UNAIDS/WHOclassification of epidemic states
Low level
Concentrated
Generalised
Source: UNAIDS
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.
Source: UNAIDS
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.
Source: UNAIDS
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.
Source: UNAIDS
UNAIDS/WHO: classification of epidemic states using numerical proxy
Low Level
HIV prevalence has not consistently exceeded 5% in any defined sub-population
Concentrated
HIV prevalence consistently >5% in at least one defined sub-populationbutbut
<1% in pregnant women in urban areas
Generalised
HIV prevalence consistently >1% in pregnant women
Source: UNAIDS
Classification of epidemic states in theWHO European Region: low, concentrated
Low level (<5%)
Concentrated (>5% in at least
one defined sub population but <1% in pregnant women
?
??
?
??
?
EuroHIV
Second generation HIV surveillanceObjectives
• Better understanding of trends over time
• Better understanding of the behaviours
• Surveillance on sub-populations at highest risk of
infection
• Flexible surveillance (moves with the needs & state of the
epidemic)
• Better use of surveillance data for prevention and care
Source: UNAIDS/WHO
HIV estimates
Biological
Indicators for HIV/AIDS surveillanceBehavioural
3,000 2,000 1,000 0 1,000 2,000 3,000
Males FemalesOther data
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
HIV estimates
Biological
Indicators for HIV/AIDS surveillanceBehavioural
3,000 2,000 1,000 0 1,000 2,000 3,000
Males FemalesOther data
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
HIV estimates
Biological
Indicators for HIV/AIDS surveillanceBehavioural
3,000 2,000 1,000 0 1,000 2,000 3,000
Males FemalesOther data
Data collection methods for HIV surveillance Other sources of information
• Death registration
• STI indicators & other biological markers of risk
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 indicatorsAge, sex, socioeconomic & educational status, indicator of residency or migration status, parity, marital status
Presentation outline
1. Second generation HIV surveillance
2. Review of the epidemiological methods used to monitor the HIV epidemic in Europe
• Case reporting
• HIV prevalence
3. Description of recent epidemiological trends
4. Example of national HIV surveillance system
Norway (P. Aavitsland)
European AIDS and HIV case reportingEuropean 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
HIV infection 1st HIV diagnosis AIDS Death
among reported AIDS cases
Source: Hamers, JAIDS 2003; 32 Suppl:S39-48
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
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
HIV / AIDS Case reporting AIDS Case definition
1982 (initial) CDC AIDS case definition
1985 CDC Revision AIDS case definition
1987 CDC Revision AIDS case definition
1993 CDC Revision AIDS case definition (USA)
1993 European AIDS case definition (Europe, Canada, Australia, Japan)
Source: European Centre for the Epidemiological Monitoring of AIDS.HIV/AIDS Surveillance in Europe: Quarterly report 37; March 1993
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
HIV / AIDS Case reportingList of AIDS indicator diseases
Burkitt's lymphoma Candidiasis of bronchi, trachea, or lungs
CMV disease or retinitis Coccidioidomycosis
Cryptococcosis Cryptosporidiosis
Extrapulmonary tuberculosis Herpes simplex virus disease
HIV encephalopathy Histoplasmosis
HIV wasting syndrome Immunoblastic lymphoma
Isosporiasis Invasive cervical cancer †
Kaposi's sarcoma Lymphoid interstitial pneumonia ‡
Lymphoma, not specified Multiple or recurrent bacterial infections ‡
Mycobacterium avium complex or M. kansasii
Mycobacterium, other or unidentified sp.
Oesophageal candidiasis Pneumocystis carinii pneumonia
Primary lymphoma of brain Progressive multifocal leukoencephalopathy
Pulmonary tuberculosis † Salmonella septicaemia
Recurrent pneumonia † Toxoplasmosis† Added in 1993 case definition ‡ in children <13 years
HIV / AIDS Case reporting Data collection & management
1. Key data extracted at national level - according to standard specifications - for each notified case
2. An anonymised version of the national dataset is sent to EuroHIV periodically. Systematic updates of data for previous years
3. Data are validated for inconsistencies, and clarifications may be requested from the correspondent
4. The finalised national datasets are merged into a common database.
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 )
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
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
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
• Complementary information (qualitative data)
• Second choice for countries without individual data
• Regular standard questionnaire and tables to fill-in
• Extensive instructions and definitions for reporting
• Occasional surveys (e.g. TB/HIV, 1995, 2003)
HIV/AIDS Case reportingAggregate data (1)
HIV/AIDS Case reportingAggregate data (2)
HIV cases reported in 2003, by half yearN.B.Totals of columns, totals of lines and the "TOTAL" table are calculated by formulae. Please do not MODIFY or remove
Country [complete] WHO code
Year of report: 2003 Half year of report:
Hom
o/b
isexual
man (
HB
M)
Inje
cting d
rug
user
(ID
U)
Do n
ot
fill
this
colu
mn.
See
note
belo
w
Haem
ophil.
/Co
agul. d
isord
er
(HE
M)
Tra
nsfu
sio
n
recip
ient
(TR
S)
Hete
rosexual
(HE
T)
Moth
er-
to-
child
(M
OT
)
Nosocom
ial
(NO
S)
Oth
er
/Undete
rmin
ed
(OT
H)
TotalAge group
<15 years
15-19
20-24
25-29
30-3940-4950+UnknownTotal
Strength & limitations of HIV case reporting
• Dependent on diagnosis (testing and care seeking) and reporting patterns
• Need for effective methods to eliminate double reports (chronic disease)
Strengths Limitations
• Overall picture of the disease burden (population-based)
• Dynamic picture of the epidemic
EuroHIV
Presentation outline
1. Second generation HIV surveillance
2. Review of the epidemiological methods used to monitor the
HIV epidemic in Europe
• Case reporting
• HIV prevalence
3. Description of recent epidemiological trends
4. Example of national HIV surveillance system
Norway (P. Aavitsland)
HIV prevalenceSentinel serosurveillance (1)
Population Institution Representativeness
STI patients STI clinics Not a reliable indicator of programme impact
IDU Treatment clinics, prisons Scope for sentinel sites limited
Sex workers Health clinics in red light districts
Regular screening for STI
Excellent, but rare sentinel site
Men who have sex with men
Health clinics in gay communities Does not exist outside the communities
Women Antenatal clinics Most accessible cross section
HIV prevalenceSentinel serosurveillance (2)
Populations regularly screened for HIV infection
• Donated blood units or blood donors
• Occupational cohorts – factory workers – migrant workers– military
HIV prevalence
Cross-sectional serosurveys in sub-populations at risk
• Attempts to get around selection bias associated with sentinel surveillance
• Sampling usually household-based
• Requires informed consent
• To track HIV prevalence among people at high risk of infection
• Require the informed consent of participants
General population-based HIV serosurveys:
HIV prevalence assessment - EuroHIV
• Data updated once a year & compiled in the European HIV prevalence database.
• Aggregate data on HIV prevalence in various populations: IDU, sex workers, MSM, pregnant women, blood donors, STI patients.
• Information recorded: - characteristics of the population tested - sampling & testing methods - numbers of subjects tested and found to be HIV+
EuroHIV
European HIV Prevalence Database
Strength & limitations of HIV prevalence assessment
• Snapshot picture of the epidemic in specific populations
• Issues of representativity
• Difficulty to interpret trends
Strengths Limitations
EuroHIV
Presentation outline
1. Second generation HIV surveillance
2. Review of the epidemiological methods used to monitor
the HIV epidemic in Europe
• Case reporting
• HIV prevalence
3. Description of recent epidemiological trends
4. Example of national HIV surveillance system
Norway (P. Aavitsland)
Definition of geographic areasused in this presentation
West401 million pop.
East287 million pop.
Centre 193 million pop.
Description of recent epidemiological trends
HIV infections
AIDS cases
HIV infections newly diagnosed per million population by geographic area, WHO European Region, 1993-2004
Excluded: Andorra, Austria, France, Italy, Malta, Netherlands, Norway, Portugal, Spain in West; Bulgaria, Croatia in Centre: national data not available for the whole period
Upd
ate
at 3
1 D
ecem
ber
2004 0
50
100
150
200
250
300
350
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
Year of report
Ca
se
s p
er
pe
r m
illio
n
East
West
Centre
EuroHIV
0
10000
20000
30000
40000
79 81 83 85 87 89 91 93 95 97
Year
Cases
Estimation of HIV incidence by HIV incidence transmission group, European Union (15 countries)
* estimated by back-calculation
HIV *AIDS
Homosexuals
IDU
Heterosexuals
Source: Downs et al.EuroHIV
HIV cases per million
200 +
100 - 199
20 - 99
< 20
Not available
Upd
ate
at 3
1 D
ecem
ber
2004
HIV infections newly diagnosed:cases reported in 2004 per million population
WHO European Region
9
NA
16
58
14
7995
712
7
54568
25
87*
32
24
40
7
17
89
48
45
30
14139
131
3
43
84
72
17
280
13
239
313
48
10931
3
0
212
122
76
10
31
NA
*Estimate based on data for half a year EuroHIV
HIV cases per million
50 +
30 - 49
10 - 29
< 10
Not available
Upd
ate
at 3
1 D
ecem
ber
200
4
HIV infections newly diagnosed:cases reported among homo/bisexual men in 2004
per million population, WHO European Region
0.3
14
0 0.5
018
0.76
3
27
8
16*
1
11
12
4
7
13
10
0.1
0
31
44
0
5
0
32
0.5
310.3
0.8
2
32
0.2
9
* Estimate based on data for half a year
NA
10
248
NA
0.3
03
0.2
EuroHIV
Upd
ate
at 3
1 D
ecem
ber
200
4
HIV cases per million
50 +
30 - 49
10 - 29
< 10
Not available
HIV infections newly diagnosed:cases reported among injecting drug users in 2004
per million population, WHO European Region
0
14
11 7
362
1
0.9
0.7
2
2
2*
21
1
0.8
0.2
3
17
9
28
24
6330
7
0
5
43
3
5
990
72
0
0
3
1117
0.01
0
120
2
31
1
0
NA NA
* Estimate based on data for half a year EuroHIV
HIV infections newly diagnosed reported in 2004: characteristics of cases by geographic area - WHO European Region
* No data for Italy, Norway and Spain; partial data for France and Netherlands† Except Romania (nosocomial ~1990) & Poland (IDU); heterosexual in Balkan countries, homosexual elsewhere
West* Centre East
Number of diagnosed cases
20 229 1 597 49 929
Highest rate per million population
280.5 (Portugal)
31.0 (Cyprus)
568.8 (Estonia)
Aged < 30 years old (%)
28% 40% 64%
Females (%) 35% 30% 40%
Predominant transmission mode
Heterosexual Low levelepidemic†
Drug injection
AIDS incidence per million population, bygeographic area, WHO European Region, 1986-2004
Data adjusted for reporting delaysFrance, Monaco, Norway, San Marino, Bulgaria, Kyrgyzstan, Russia, Uzbekistan excluded:national data not available for the whole period
Upd
ate
at 3
1 D
ecem
ber
2004
0
10
20
30
40
50
60
1986 1988 1990 1992 1994 1996 1998 2000 2002 2004
Year of diagnosis
Ca
se
s p
er
mill
ion
HAART
East
West
Centre
EuroHIV
The four most common AIDS indicative diseases (%) among AIDS cases diagnosed in 2004
West, Centre and East, WHO European Region
Upd
ate
at 3
1 D
ecem
ber
200
4
0
10
20
30
40
50
60
West Centre East
% o
f ca
ses
Tuberculosis P. carinii pneumonia
Oesophageal candidiasis HIV wasting syndromeEuroHIV
East: Baltic States
PopulationLithuania: 3.4 millionLatvia: 2.3 millionEstonia 1.3 million
EuroHIV
0
200
400
600
800
1000
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Year of report
Latvia
Estonia
Cases per million
HIV infections newly diagnosed per million population, Baltic States, 1994-2004
Lithuania
Upd
ate
at 3
1 D
ecem
ber
200
4
EuroHIV
0
100
200
300
400
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
Year of report
Cases
Homo/bisexual men
Injecting drug users
Persons infected heterosexually
HIV infections newly diagnosedby transmission group, 1994-2004, Lithuania
Total
Upd
ate
at 3
1 D
ecem
ber
200
4
EuroHIV
0
10
20
30
40
1988 1990 1992 1994 1996 1998 2000 2002 2004
Year of diagnosis
Cases per million Latvia
AIDS cases per million populationin the Baltic States, 1988-2004
Data adjusted for reporting delays
Estonia
Lithuania
Upd
ate
at 3
1 D
ecem
ber
200
4
EuroHIV
Prevalence data
Description of recent epidemiological trends
HIV prevalence among high risk populations bygeographic area, WHO European Region, 2000-03
West Centre East
Injecting drug users
<5% in 11 countries>20% in Mediterranean countries
<2% in all countriesexcept Poland (>20%)
5% in some countriesUp to 60% in cities in Ukraine & Russia
Homosexual men
5-15% 3-10% 0-5%
Sex workers Mostly <1% <1% Up to 15%
STI patients 1-2% <0.1% 0-2%
EuroHIV
0
10
20
30
40
1991 1993 1995 1997 1999 2001 2003
% HIV+Belgium (French community, DTC; SR)
France (DTC; SR)
France (RC; SR)
Italy (DTC; SP)
Portugal (DTC; DT mean of 3 studies)
Spain ( VCT, STI; DT)
Spain ( DTC; DT)
Switzerland (VCT; DT)
Germany (DTC; SR)
England & Wales (multiple sites; SP)
Poland (VCT, DTC, STI; DT)
EuroHIV
Upd
ate
at 3
1 D
ecem
ber
2003
HIV prevalence (%) among injecting drug users:prevalence studies and diagnostic testing,
western and central Europe,1991-2003
SR = Self reported HIV status DTC = Drug treatment centres VCT = HIV voluntary counselling & testing centresSP = Seroprevalence studies RC = Residential centres for ex-drug users STI = STI clinics DT = Diagnostic testing Multiple sites = DTC, needle exchange programmes, low threshold services for drug users, street, hospitals
0
5
10
15
20
25
1993 1995 1997 1999 2001 2003
% HIV+
Belarus (DTC, hospitals)
Estonia (multiple sites)
Georgia (DTC)
Armenia (DTC)
Latvia (DTC, hospitals)
Lithuania (DTC, NEP, hospitals)
Moldova (DTC, VCT)
Russian Federation
Ukraine
Upd
ate
at 3
1 D
ecem
ber
2003
HIV prevalence (%) among injecting drug users:diagnostic testing studies in countries of
eastern Europe, 1993-2003
DTC = Drug treatment centresNEP = Needle exchange programmes VCT = HIV voluntary counselling & testing centresMultiple sites = NEP, DTC, VCT, General practitioners, STI clinics EuroHIV
0
2
4
6
8
10
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002Year
HIV prevalence (%) among female sex workers: prevalence studies & diagnostic testing (DT),
western & central Europe, 1992-2002
% H
IV+
Spain (6 cities*), STI patients
Scotland - DT
Rome**
Spain (9 cities)** - DT
Poland† - DT
* Alicante, Bilbao, Gijon, Madrid, Oviedo, Pamplona
† male & female prostitutes; ** most HIV+ are injecting drug users
Upd
ate
at 3
1 D
ecem
ber
2002
Vienna, illegal prostitutes** - DT
Prague + 2 regions
EuroHIV
0
10
20
30
40
50
1996 1997 1998 1999 2000 2001 2002Year
HIV prevalence (%) among female sex workers: prevalence studies, eastern Europe, 1997-2002
% H
IV+
Armenia
Saint Petersburg
Belarus
Riga Vilnius
Upd
ate
at 3
1 D
ecem
ber
2002
Moscow
Kaliningrad
Riga
EuroHIV
Conclusion: implications for public health
HIV remains a major public health problem in both western and eastern Europe
To diagnose and provide effective treatment to all infected persons is a challenge throughout Europe
In western Europe, prevention and care must be adapted to reach migrant populations; renewed safer sex campaigns targeted at MSM are needed
In eastern Europe, HIV prevention among IDU should be the cornerstone of HIV prevention strategies; at the same time, preventing further heterosexual transmission is critical