Serosurveys in household samples HIV Seroprevalence in DHS Mali, West Africa, 2001

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Serosurveys in household samples HIV
Seroprevalence in DHS Mali, West Africa, 2001

• Caroline A. Ryan MD, MPH
• Global AIDS Program
• Division of STD Prevention
• NCHSTP

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MAP Durban Lazzari Conclusions

• Adding HIV testing to population-based surveys is
  technically feasible but raises serious
  logistical and ethical concerns
• Several options exist for testing protocols and
  methods.
• Must be seen as an addition and not a replacement
  for HIV sentinel surveillance
• Field testing is required

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Outline

• Options for adding HIV when should it be done?
• Ethical considerations
• Informed consent
• Confidentiality
• Survey to service continuum
• Challenges of implementation
• But is adding HIV to household serosurveys really
  necessary is ANC surveillance good enough?

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Challenges

• Logistics
• Cost
• Informed consent
• Impact on DHS response rates/team function

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Population-Based HIVSero-surveys

• Capture the epidemiological diversity of an
  epidemic
• HIV prevalence in men
• HIV prevalence in rural areas
• Regional data
• Calibrate sentinel surveillance data
• Include behavioral data
• Allow behaviors to be linked to HIV prevalence
• Explain changes in an epidemic

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The Demographic and Health Survey (DHS)

• Nationally representative household surveys
  (5,000 to 100,000 households)
• Questionnaire on basic socio-demographic and
  health indicators
• Collection of blood samples for hemoglobin
  testing
• Conducted every 5 years

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Options for adding HIV to household surveys

• Option 1
• Voluntary Confidential HIV Testing
• Option 2
• Unlinked Anonymous HIV Testing (with consent)
• Option 3
• Unlinked Anonymous HIV Testing (without consent)

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DHSHIV (option 1)Voluntary Confidential HIV
Testing

• Advantages
• Informed consent
• Linking serological and behavioural data
• HIV positives respondents can be informed

• Problems
• Refusal/participation bias
• Confidentiality may be an issue
• Confirmation required
• Counselling must be available
• Treatment?

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DHSHIV (option 2)Unlinked Anonymous HIV Testing
(with consent)

• Problems
• Refusal/participation bias
• Infected respondents cannot be informed
• Only limited links with behavioural data
• Respondent might ask to know the results of the
  test

• Advantages
• Informed consent
• Less complex
• Preserves anonymity
• No need for confirmation

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DHSHIV (option 3)Unlinked Anonymous HIV Testing
(without consent)

• Advantages
• Less complex
• Ensures anonymity
• No participation bias
• No consent
• No confirmation
• No counselling

• Problems
• Infected respondents cannot be informed
• No linking with behavioural data
• Appropriate samples must be regularly collected
• Considered not ethical in several countries

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Considerations in Adding HIV to DHS

• Prevalence of HIV
• Political will
• Other sources of information
• Data needs
• Data on inequality in health are needed for sound
  public health planning and implementation
• Data are needed for by major geographic region
  within the country, by urban and rural areas, by
  ethnic group or race, by level of education, etc.
• Phase of the epidemic ?

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Ethical considerations

• How do we guarantee anonymity?
• How do we assure the consent process is as
  informed as possible?
• F/U of a positive result
• Should treatment and/or counseling be provided to
  respondents?
• Accessibility of follow-up services - rates
  usually low

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Objectives

• To demonstrate the feasibility and acceptability
  of adding serologic testing for HIV to a
  standardized national health survey
• To illustrate the important data that can be
  derived from such a survey
• To provide national HIV prevalence data to the
  Malian Ministry of Health

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Methods

• A nationally representative population-based
  sample of households
• Household interview
• Individual interviews and hemoglobin testing
• Every interviewed man and every third interviewed
  woman offered HIV testing

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Methods HIV Testing

• Finger stick blood on filter paper
• Two HIV ELISAs
• HIV testing voluntary and anonymous with informed
  consent
• Unlinked to DHS interview responses
• Limited demographic information
• Individuals referred for free counseling and
  testing

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Initial Phase

• Pilot testing in Bamako
• Interview
• Interview anemia
• Interview anemia and HIV
• Qualitative work on participants understanding of
  informed consent and follow-up VCT

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Provisions for participants

• Pretest counseling - Informed consent
• Educational information
• Card for free VCT
• 58 VCT centers established throughout country as
  well as mobile vans- (rapid tests)
• 6 months free testing at VCT centers
• TV and radio promotion of VCT facilities

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Results

• 13,717 nationally representative households
  sampled
• 12,331 households completed interviews
• Individual interviews completed by 12,849 women
  and 3,405 men
• HIV testing performed on 3,845 women and 2,962 men

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Acceptance Rates forDHS Interview and HIV Testing
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HIV Prevalence by Age Group, Sex, and Urban or
Rural Residence
Prevalence estimates are given as percentages
-- Women aged 50-59 are not included in the DHS
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Behavioral Data by Geographic Circle
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Cost of adding HIV testing
 
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Next Steps

• Malian government reinstating sentinel
  surveillance at ANC clinics
• DHS with HIV testing
• MACRO International and national ministries of
  health
• Dominican Republic saliva
• Zambia HIV test results linked to data from the
  individual interview

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But is adding HIV to household serosurveys really
necessary is ANC surveillance good enough?
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ANC and population based data

• Seven recent studies (6 Africa and 1 in Cambodia)
• Sources of bias - biologic factors (sub
  fertility) and behavior (age of sexual debut,
  contraception use, ANC use and differential
  patterns of ANC use)
• A procedure for adjusting HIV prevalence
  estimates obtained from ANC women proposed by
  Zaba et al. takes account of underlying
  differences in fertility and related behavior.
  This procedure works well in high fertility
  settings and is reasonably robust to changes in
  population structures
• DHS data on fertility and its proximate
  determinants need to be maintained to monitor
  changes in fertility-related behavior

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Characteristics of Population
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Percent ANC utilization and Estimated Prevalence
and Numbers of HIV Infections by Region
51
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ANC Utilization
61
36
46
54
60
63
93 93
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Conclusions

• Serologic HIV testing added to DHS
• Feasible
• Acceptable
• Yields data of practical importance
• Current HIV prevalence data in Mali
• Yielded valuable data on rural populations and on
  men
• Potential use for linked data (unlinked/linked)
  and discordant couples data

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Acknowledgements

• Malian Ministry of Health
• Isaaka Niambélé
• Salif Ndiaye
• Seydou Ba
• MACRO International
• Gregory Pappas
• Casey Aboulafia
• Almaz Sharman
• USAID Mali
• Aida Lo
• Ursula Nadolny
• Salif Coulibaly

• Mali National Institute for
• Public Health Research
• Flabou Bougoudogo
• GAP
• George Bicego
• Christopher Murrill
• DSTDP
• Rachel Bronzan
• Enias Baganizi
• Ellen MacLachlan
• Saran Sidibé

WHO
Dr Stefano Lazzari