HIV and TB
Prevention and treatment
What multi-sectoral strategies will
decrease the burden of infectious disease
amongst the people of the Western Cape?
A coherent strategy needs to be informed by the
answers to the following questions…
• What is the scale of the HIV/TB epidemic in the Western
Cape?
• Where is it prevalent?
• Why does it occur where it does?
• What tools do we have to either prevent infection or to
reduce disease severity, and how effective are they?
Scale and distribution of disease
HIV infected population in the Western Cape
+ ART coverage
District/Sub-district No. HIV infected
Khayelitsha
39 121
Cape Winelands
29 371
Klipfontein
29 205
Eastern
26 508
Western
22 894
Northern
22 862
Eden
22 271
Mitchells Plain
17 962
Southern
16 300
Tygerberg
16 193
Overberg
14 521
West Coast
9 114
Central Karoo
3 680
270 000
Proportion of
total infections
No. on ART
Proportion of
total on ART
14.5%
19 708
19.1%
10.9%
10 477
10.1%
10.8%
7 863
7.6%
9.8%
9 506
9.2%
8.5%
11 499
11.1%
8.5%
5 385
5.2%
8.2%
8 381
8.1%
6.7%
11 273
10.9%
6.0%
5 764
5.6%
6.0%
6 147
5.9%
5.4%
3 268
3.2%
3.4%
3 570
3.5%
1.4%
508
0.5%
100.0%
103 349
100.0%
TB cases 2009
West Coast: 4,244 (8%)
Central Karoo
Overberg
West Coast
Eden
Cape Town…
35000
30000
25000
20000
15000
10000
5000
0
Cape Winelands
TB cases
Central Karoo: 700 (1%)
Cape Winelands: 9,892 (18%)
Cape Town: 30,820 (55%)
Overberg: 3,059 (5%)
Eden: 7,204 (13%)
TB is the face of HIV
• Being HIV-infected increases your risk of having TB by anywhere
from 30 to 100-fold (depends on the stage of the HIV disease)
• Proportionate to its population size, Western Cape is the province
worst affected by TB
TB is what is killing HIV-infected people
Recent HCT campaign
Sites with > 1000 HIV+ tests – Red
Sites with 400-1000 HIV+ tests - Yellow
Burden of HIV and TB
~270,000 HIV infected individuals
~50,000 diagnosed TB cases per annum
Of HIV-infected people, 86% are in 14 sub-districts
Of TB diagnoses, 76% are in the same 14 sub-districts
These two diseases account for +/- a quarter of the years of life lost in the province
Why do certain areas carry a disproportionate
burden of HIV disease?
Because they harbour many of the risk factors
associated with HIV1:
The ‘deprivation cluster’ of:
1. Poverty
2. Overcrowding
3. Malnutrition
4. Migration
Produce social vulnerability
1. Western Cape Burden of Disease report for major infectious diseases, 2007
Social vulnerability creates a high risk environment
for HIV transmission
By being strongly associated with the following risks1:
1.
2.
3.
4.
5.
6.
7.
Not knowing one’s HIV status
Stigma and discrimination
Age mixing
Early sexual debut
Transactional sex
Partner turnover/concurrency
Alcohol misuse
*disempowerment
*compromised decision-making
*economic necessity
1. Western Cape Burden of Disease report for major infectious diseases, 2007
Despite the socio-structural environment creating a context of high risk
for HIV acquisition…
the final mediator of HIV transmission is biological
Viral transmission is a complex biological sequence of events that
starts with ‘permanent’ viral attachment to host epithelial tissue
Some people are more likely to transmit HIV and others are more vulnerable to acquire HIV
1.
2.
3.
4.
5.
Sex & age
Viral load
Sexually transmitted infections
Lack of circumcision
Mother to child transmission
TB – another risky environment
Risk 1 = Risk of being exposed to the organism
(acquiring infection)
• The ‘deprivation cluster’ of: impoverishment, poor nutrition,
migration, overcrowded dwellings compounded by existing high TB
prevalence and incidence, poor education, ignorance of TB
transmission mechanisms and of TB symptoms, poor adherence to
treatment
“85-90% of those people with normal immunity who inhale TB do not develop disease”
TB – another risky environment
Risk 2 = Risk of infection progressing to disease
TB infection can be longstanding and “reactivate”
or can be recently acquired and progressive
“50-90% of South Africans are likely to be latently infected with TB”
“by far the most powerful risk identified (for infection progressing to disease) is
concurrent HIV infection”
Interventions
• We’re not only trying to prevent new HIV and new TB infections
• We also have a large population of people who are already HIVinfected, and in whom we are trying to prevent premature death
HIV prevention can and should be implemented at
different levels
Biomedical – attempt to block infection or reduce
infectiousness
Behavioural- attempt to motivate behavioural
change within individuals or communities
Structural- seek to change the context that
contributes to vulnerability or risk
Biomedical interventions need to be placed into the high risk environments - at scale
(and socio-structural barriers to their consistent and correct use need to be
overcome)
Level of
intervention
Risk
No.
Prevention method
1 Barrier methods
2
Biomedical
HIV in body fluids
coming into
contact with
epithelium of
sexual partner
3
STI treatment
Mode of action Effectiveness
Physical seperation
Restore epithelial
integrity
Reduce epithelial
vulnerabilty
Reduce hiv in body
fluids
Reduce hiv in body
fluids
85-95%
Variable
Male circumcision
~58%
Oral ARTtheoretically
lifelong
very high
AntiOral ART4 retroviral pre-coitally
~44%
medication Topical
antimicrobials Reduce probability
peri-coitally
of viral 'attachment' ~39%
5 Vaccines
Boost immunity
unclear
TB interventions
1. Reduce the probability of someone inhaling the
mycobacterium Tuberculosis
– Tackle the ‘deprivation cluster’ – overcrowding etc
– Reduce prevalent and incident TB (case-finding – ART work-up,
door-to-door community drives etc..)
– Reduce/prevent drug-resistant TB
– Reduce infectiousness of those with TB (case-treatment and caseholding)
– Environmental infection control (applying not only to health
facilities but all areas where people congregate – transport, work,
church, bars etc)
TB interventions
2. Reduce the probability of inhaled (or latent) tuberculosis
progressing to active disease
– Early identification of high risk cases (HIV testing) and intensive
education of disease symptoms
– Regular routine monitoring of high risk cases
– ‘Bolster immunity’: ART where indicated
– IPT where appropriate
A word on Mother-to-child transmission
Pre-conception
MTCT – effective contraception is a
powerful tool to prevent transmission of HIV from
mother to child. 100% effective
Pre-partum
Antiretroviral drugs (dual and triple therapy)
reduce viral load, reduce probability of
transmission. The earlier started, the better
Intra-partum
Antriretroviral drugs and reducing birth trauma
(C/S)
Post-partum
Antiretroviral drugs for mother and child.
Breastfeeding choices and drug cover to
the child for the duration of breastfeeding
We know the following about HIV infections in
the Western Cape…
• In the absence of a ‘game-changing’ intervention, the Western Cape
will see approximately ~14,000 HIV infections in 2012 (~1,200 of
which will be from mother to child)
• We can identify the communities in which the ~14,000 transmission
events will occur
• We have the biomedical tools and knowledge to theoretically stop
almost every one of those transmission events…
But we’re missing a piece of the puzzle…
And it revolves around generating large scale demand for, and
consistent uptake of, proven biomedical interventions by high risk
communities
It’s not clear how we are going to solve this vexed problem,
but let’s try and picture the type of societal and community
norms that would be required to reduce HIV and TB
transmission…
What’s the “ideal world” scenario?
• Structural: to do away with the ‘deprivation cluster’
• Societal/behavioural:
An environment in which everybody…
• Is informed of the consequences of HIV infection, knows their HIV status,
checks it regularly and no stigma is attached to doing so
• Uses barrier protection consistently, and especially with casual sex; has
immediate access to condoms whenever they want them and their use of
condoms is positively re-enforced by their partner, their peer group and
their community
• Delays their sexual debut and avoids having multiple sexual partners
• Men present for circumcision routinely
• Women use contraception consistently and space their pregnancies well
• HIV-infected pregnant women know their HIV status and present very
early in their pregnancy for treatment
What’s the “ideal world” scenario?
• Societal/behavioural:
An environment in which every HIV-infected person…
• Knows that they are at unusually high risk of TB
• Knows how to recognise TB, knows simple household and community
infection control measures, knows the benefits of TB preventative therapy,
knows what to do and where to go if they think they have TB
• Who is HIV-infected is able to keep themselves well by routinely
undergoing monitoring (for TB, cervical cancer etc) and being rapidly
responsive to new symptoms
What’s the “ideal world” scenario?
• Biomedical
An environment in which everybody…
• Has simple and rapid access to HIV and TB testing
• Has easy access to required medication
• Adheres to their prescribed treatment because they understand it benefits
them, are aware of the consequences of not doing so, and are supported
in doing so by their peers and their community
UNAIDS suggested high level strategies…
•
•
•
•
•
“Highly active HIV prevention inevitably must be combination prevention”
“Nothing should be more important than a focus on young people”
“investments should focus on promoting normative and social change to
reduce multiple and concurrent partnerships, and to greatly increase
availability of safe and affordable male circumcision services”
“condoms (unlike contraception) have to be available immediately and thus a
continuous source of supply is needed”
“The aggregate effect of radical and sustained behavioural changes in a
sufficient number of individuals potentially at risk is needed for successful
reductions in HIV transmission”
“ Understand but don’t overcomplicate.
Broad rapid brushstrokes are sufficient for action”