2nd generation HIV surveillance - PowerPoint by GEoe5NK3

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									Key concepts in the 2nd
 generation HIV/ AIDS
     surveillance



“Second Generation HIV Surveillance” (SGHS)
      Content of the presentation

•   Objectives of surveillance systems for
    policy making
•   Methods and data sources
•   From data to information
•   Principles underlying 2nd generation HIV
    surveillance
•   Components in low level and concentrated
    epidemics
Rationale for Disease Surveillance
• Public health importance of disease ?

• Can public health action be taken ?

• Are relevant data easily available ?

• Is it worth the effort (money,
   human resources)?
        What are the
objectives of surveillance ?
        Aims of surveillance
to give up to date information on the state of
  infectious diseases:
for control and prevention

to assist in policy making

to improve epidemiological
research
     Surveillance: “data for action”

Surveillance is the ongoing systematic
  collection, collation, analysis and
    interpretation of data; and the
   dissemination of information to
  those who need to know in order
       that action may be taken
    2nd Generation HIV Surveillance,
            main objective:
To monitor HIV and high-risk behaviour trends over
  time in order to provide essential data needed for
  the development of interventions and the
  evaluation of their impact

= to provide a more comprehensive understanding
  of the HIV epidemic

 effective coordination between surveillance and
  prevention programmes needed
  2nd generation HIV surveillance

                 HIV              STI
             surveillance     surveillance
  AIDS                                       behavioural
reporting                                    surveillance


                 Data management



            HIV estimates and projections



                Use of data for action

                                                       Source: WHO
2nd HIV surv.: data collection methods
     “RISK”      HIV INCIDENCE         HIV PREVALENCE                AIDS CASE     AIDS
  SURVEILLANCE   SURVEILLANCE           SURVEILLANCE               SURVEILLANCE   DEATHS




                                 VIRAL LOAD       HIV ANTIBODIES




             “WINDOW”
              PERIOD             ASYMPTOMATIC PERIOD               HIV ILLNESS
      INFECTION                                                       or AIDS     DEATH
         HIV infections newly diagnosed by transmission group
                       1994-2002, western Europe*

                                      Cases                                                              Persons infected
                               6000
                                                                                                         heterosexually (HC)

                               5000
                                                                                                         HC from country
                                                                                                         with generalised
                               4000                                                                      epidemic
                                                                                                         Homo/bisexual men
                               3000


                               2000                                                                      Risk not reported
Update at 30 June 2003




                               1000
                                                                                                         Injecting drug users
                                  0
                                  1994        1995   1996     1997     1998      1999   2000   2001   2002
                                                                  Year of report
                                                                                                                   EuroHIV
                         * Belgium, Denmark, Finland, Germany, Greece, Iceland
                          Luxembourg, Norway, Sweden, Switzerland, United Kingdom
 Epidemiologic Principles Underlying HIV
              Surveillance


• HIV infections are not uniformly distributed
  in a population


• HIV infection enters into different
  geographic areas and populations at
  different times, and spreads at different
  rates

                                                 #3-2-10
   HIV/AIDS Surveillance in the First
       Decade of the Epidemic

• Mainly HIV sentinel surveillance and
  AIDS reporting
• Did not make best use of other data
  sources
• Provided poor early warning
• Ignored at-risk subpopulations
            Second-Generation HIV
                Surveillance
• Developed by the WHO and UNAIDS as a response to the
  increasing complexity of the HIV epidemic

• Comprises of more sophisticated surveillance activities
  and provides a more comprehensive understanding of
  epidemic trends

• Improves effectiveness of control and prevention efforts

• HIV/AIDS surveillance is one of the key elements of any
  HIV/AIDS programme
• Tailor surveillance to local situation
• Target locally relevant groups and behaviours
• Focus on new infections/ risk – maximum
  impact
• Importance of quality: critically examine quality
  of our systems

Importance for planning programmatic responses
• Get ahead of the epidemic instead of playing
  “catch-up”
         State of HIV Epidemics

Low Level Epidemics
HIV <5% in all sub population with high risk behaviour

Concentrated Epidemics
HIV >5% among in any subpopulation with high risk
behaviour and < 1% among women attending
antenatal clinic

Generalized Epidemics
HIV > 1% among women attending antenatal clinic (in
general population)
                                             Source: WHO
   Patterns of HIV epidemics in the world




Type of the epidemic
   Generalized
   Concentrated
   Low Level
   No Data



                                  Source: WHO
        AIDS case surveillance

LIMITATIONS
•   Accuracy of information (under diagnosis)
•   Rate of notification (under reporting)
•   Delay on reporting
•   Different AIDS case definitions
•   Limited reporting from private sector




                                        Source: WHO
           Overview of HIV
            Surveillance
• There are two general approaches to
  HIV surveillance:
  – HIV case reporting
  – HIV sero-surveillance

• Surveillance activities can either be
  active or passive.

                                          #3-1-7
Quality of sero-surveillance systems




           Sero-surveillance system quality
            Fully implemented systems

             Some aspects of a fully implemented system

             Poor or non-functioning system               Source: WHO
         Current Challenges in Eastern
                   Europe
• West
  – Maintain preventive behaviour
  – Promote access to diagnostic testing and care for
    infected individuals

• Central
  – Maintain low level transmission

• East
  – Control current epidemics in IDU
  – Prevent sexually transmitted HIV
  – Provide access to diagnostic testing and care for
    infected individuals
STI Surveillance as Component of
 2nd Generation HIV Surveillance


– STI as a measure of HIV risk
– Biologic and epidemiologic evidence that STI
  facilitate the spread of HIV
– Role of STI treatment in prevention of HIV
What is behavioural surveillance?

• BSS is a monitoring and evaluation
  tool designed to systematically monitor
  trends in HIV risk behaviors over time in
  key target groups
• BSS is carried out through a series of
  repeated cross-sectional surveys
  conducted at regular intervals on a
  national or regional scale
  Use of behavioural surveillance
          surveys (BSS)
• Information: informs program designs and serves as
  an early warning system
• Evaluation: provides documentation of behavior
  change over time (in response to interventions)
• Triangulation: contributes to biological and
  behavioral surveillance systems to provide additional
  data for HIV/AIDS estimates and projections

  Note: Behavioral data does NOT draw a direct
  causal link between particular interventions and
  particular levels of behavior change
     Target populations for HIV
surveillance in low and concentrated
              epidemics

 • Injecting drug users (IDUs)
 • Female and male sex workers
   (FSW, MSW)
 • Men who have sex with men
   (MSM)
 • Prisoners
 • TB patients
 • Men on the move (MOM, truckers)
HIV/STI transmission dynamics at
         population level

                    General population

        Bridging population


 High frequency
  transmitters
   HIV and behavioural surveys

• Refusal rate is usually higher for HSS
• Objectives of surveys are different
  – Sample sizes
  – Groups may not overlap
     • HIV and not BSS – STI, ANC, TB
     • HIV and BSS – FSW, IDU, youth
Sentinel sites for hard-to-reach
          populations
– STD clinic (FSW, MSM)

– Special clinic (FSW, MSM)

– Drug treatment program, needle exchange program
  (IDU)

– TB patients

 Sentinel sero-surveillance is the mainstay of
 HIV/AIDS surveillance in many developing
 countries
Criteria for 2nd generation surveillance
• Surveillance systems should be appropriate to the
  epidemic state and dynamic

• Surveillance systems should use resources efficiently,
  focusing on populations at particular risk

• Behavioural data should be used to guide biological data
  collection and explain trends in HIV infection




                                                   Source: WHO
     2nd generation HIV surveillance
• Limitations of (sexual) behaviour data
  – Specificity and sensitivity of questionnaires
  – Cost and complexity of quality studies
• Adding STI data could improve on both specificity
  and sensitivity by using “objective” laboratory tests
• Advantages of “triangulation” (HIV, STI &
  behavioural data)
• Ability to detect change
• More timely for prevention
                                               Source: WHO
 2nd HIV surveillance: providing key answers

    HIV
                              Questions for surveillance
 epidemic

               • Any risk behaviour leading to HIV epidemic?
 Low-level
               • Sub-populations with risk behaviour?
    and
               • Sub-populations: size? HIV prevalence? Behaviours?
Concentrated
               • Links between these sub-populations and general pop.?

               • What are the trends in HIV infection?

               • Do trends in behaviour explain trends in HIV prevalence?
Generalized
               • Impact of interventions on risk behaviours?

               • Impact of HIV epidemic on individual, family and country?
             The full surveillance cycle

                            Identify sub-               Pre-surveillance
                            populations at risk of      assessments using
                            HIV infection               rapid/qualitative techniques


Plan for next round
of surveillance
                             IDUs?
                             MSM?
                             SWs?                      Reach consensus on
                             All?                      groups to include in
                             Sub-groups?               surveillance

Use data to strategically
target interventions
and/or monitor ongoing
intervention effects                   Conduct surveillance
Strategic Goals of HIV prevention
          programmes
• Reduce the transmission
  – Lowering the risk of STI/HIV transmission –
    targeted interventions
• Reduce the vulnerability
  – Prolonging and improving the quality of life –
    treatment and care of STI/HIV and related
    morbidity and disability
• Reduce the impact
  – Promoting enabling health sector policies and
    institutional environments
Have data. Now what?
            Key questions

• How well are we meeting the 2nd
  generation goals in Croatia?
• Are serosurveillance systems being
  tailored to the local situation?
• Are we collecting the appropriate
  biological and behavioural data for the
  state of low-level epidemics?

								
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