Epidemiological surveillance of HIV infection & AIDS in Europe Advanced course in epidemiology of...

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)

[email protected]

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


3,000 2,000 1,000 0 1,000 2,000 3,000


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


3,000 2,000 1,000 0 1,000 2,000 3,000


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



2. Review of the epidemiological methods used to monitor the HIV epidemic in Europe

• Case reporting

• HIV prevalence


4. Example of national HIV surveillance system


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



2. Review of the epidemiological methods used to monitor the

HIV epidemic in Europe

• Case reporting

• HIV prevalence




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



2. Review of the epidemiological methods used to monitor

the HIV epidemic in Europe

• Case reporting

• HIV prevalence




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


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


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

Epidemiological surveillance of HIV infection & AIDS in Europe Advanced course in epidemiology of...

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