Ending AIDS Past, Present and Yet to Come Brian Williams Newton Institute August 2013 Ask not what public health can do for epidemiology but what epidemiology can do for public health (With apologies)
Dec 25, 2015
Ending AIDSPast, Present and Yet to Come
Brian WilliamsNewton Institute August 2013
Ask not what public health can do for epidemiology but what epidemiology can do for public health (With apologies)
The philosophers have only interpreted the world, in various ways; the point, however, is to change it.
In France the controversy [about whether or not inoculation was a good thing] was brought to an end by the death of Louis XV
T.W. Körner
Marx, K. (1845) Theses on Feuerbach
A cautionary tale
Where science and politics meet
Chris Dye: Modelling is still not on the radar screen of public health
Medical students were doing autopsies before coming into the maternity wards but mid-wives were not.After 1839 students no longer came into the red ward and maternal mortality dropped.In 1848 he introduced hand-washing and mortality dropped in the blue wards.In 1849 he was fired for criticizing his superiors. In 1865 he died of septicaemia in an asylum.
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1830 1835 1840 1845 1850 1855 1860
Mat
erna
l mor
talit
y
dismissed
Only midwives in red clinic
Semmelweiss
Semmelweiss introduces hand washing in blue clinic
Ignaz Philipp Semmelweiss (1818 –1865)
A VERY brief history of HIV/AIDS
1980s: Basic epidemiology established
• Routes of transmission understood• Initial doubling time: 2 to 5 years• Survival: Weibull (2.25; 11 years)• Risk per sexual encounter: 0.001• Other STIs enhance transmission• R0 ~ 7• Diagnostic test developed• First anti-retroviral drug available
1990s: Drugs, risk-groups and impact
• Triple therapy available (very expensive)• IDU & MSM in developed countries; IDU
& FSW in Asia; heterosexual in Africa• Nine worst affected countries in the
world in southern Africa; North India 200x less than South Africa.
2000s: Cheap drugs, lots of money, 3x5, what doesn’t work
• Drug prices fall by 1000x• Behaviour change; condoms; STI
treatment don’t really work• CD4: marker of progression• Viral load: marker of survival and
infectiousness• Vertical transmission can be stopped
2010s: What works• Male circumcision: 60% reduction• PreP: 40% reduction• ART reduces viral load from 100,000 to
10/mL.• ART cost US$100 p.a.; well tolerated;
resistance falling.
What if….
…we had started to treat early and hard in 1995…..
David Ho 1995
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1980 2000 2020 2040
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0.010
0.020
Pre
vale
nce
Inci
de
nce
an
d m
ort
alit
y/yr
Base line
Prevalence
Off ART On ART Off ART On ART
HIV in South Africa: test and treat starting in 1995
Prev.
Inc.
Mort.
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1980 1990 2000 2010 2020 2030 2040 2050
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0.010
0.020
Pre
vale
nce
Inci
denc
e an
d m
orta
lity/
yr
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0.20
1980 1990 2000 2010 2020 2030 2040 2050
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0.020
Pre
vale
nce
Inci
denc
e an
d m
orta
lity/
yr
0.00
0.05
0.10
0.15
0.20
1980 1990 2000 2010 2020 2030 2040 2050
0.000
0.010
0.020
Pre
vale
nce
Inci
denc
e an
d m
orta
lity/
yr
Incidence
Mort.
Mortality
What about adolescents?
Age (years)
Sur
viva
l
Survival of children born with HIV in Africa Marston JAIDS (2005) 38: 219
Case study: 200632 adolescents presenting with HIV in Harare. Most were severely stunted and suffering from AIDS defining illnesses. Median CD4+
100/L, median age 11 yrs, 55% double orphans
Ferrand CID (2007) 44:874
Two 16 year old children. The child on the right has been in a wheel chair with arthritis since the age of five.
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2.5
10
20
30
40
5070 60
Years since infection
Pro
port
ion
surv
ivin
gSurvival against age at HIV seroconversion
from the CASCADE study
CASCADE Lancet (2000) 355: 1131-1137.
P
ropo
rtio
n su
rviv
ing
(%)
Age (years)
0
20
40
60
80
100
0 5 10 15 20
Combine the data on very young children with the data from the CASCADE study
Age (years)
Pre
vale
nce
of H
IV
Num
ber
of c
hild
ren
1995
2000
2005
2010
2015
2020
Predicted prevalence of HIV in South African children and the number of AIDS orphans being maintained on ART by the Catholic Bishops conference in 2007
Ferrand CID (2007) 44:874
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0 5 10 15 20Age (years)
Pre
vale
nce
Botswana
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Pre
vale
nce
South Africa
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Pre
vale
nce
Swaziland
Predicted and observed prevalence of HIV in adolescents in 2003
Ferrand CID (2007) 44:874
Treatment guidelines
The effect of treatment guidelines on the number of people eligible for
treatment: 2000-2002
DHHS; IAS; WHO
DHHS (2000) http://guideline.gov/content.aspx?id=36814; Carpenter et al. JAMA (2000) 283: 381-390; World Health Organization, Geneva (2002)
Probability of developing an AIDS related illness in 3 years DHHS data from the MACS cohort, 2000
DHHS; USA (2000) http://guideline.gov/content.aspx?id=36814
0
1000
0 7
20
40
Likelihood (%) of developing an AIDS related illness in 3 yearsAnalysis of MACS data. DHHS 2000; IAS 2000; WHO 2002
5
90% eligibleDHHS 2000: All to the right and below the lines should start ART. The rest should not. In South Africa 90% of all HIV positive people were eligible for ART.
10
Young menOrange Farm2000
Carpenter et al. JAMA (2000) 283: 381-390; DHHS (2000)http://guideline.gov/content.aspx?id=36814; WHO (2002) www.who.int
0
1000
0 7
20
40
Likelihood (%) of developing an AIDS related illness in 3 yearsAnalysis of MACS data. DHHS 2000; IAS 2000; WHO 2002
5
90% eligible
IAS 2000: All to the right and below the lines should start immediately. Between the lines consider treatment. Top left don’t start.In South Africa in 2000 90% of all HIV positive people were eligible for ART.
90% eligible
10
Young menOrange Farm2000
Carpenter et al. JAMA (2000) 283: 381-390; DHHS (2000)http://guideline.gov/content.aspx?id=36814; WHO (2002) www.who.int
0
1000
0 7
20
40
Likelihood (%) of developing an AIDS related illness in 3 yearsAnalysis of MACS data. DHHS 2000; IAS 2000; WHO 2002
5
10% eligible
WHO 2002:Only those below the line should start ART. In South Africa10% of all HIV positive people were eligible for ART 10
Young menOrange Farm2000
Carpenter et al. JAMA (2000) 283: 381-390; DHHS (2000)http://guideline.gov/content.aspx?id=36814; WHO (2002) www.who.int
0
1000
0 7
20
40
Likelihood (%) of developing an AIDS related illness in 3 yearsAnalysis of MACS data. DHHS 2000; IAS 2000; WHO 2002
5
90% eligible
10% eligible
90% eligible
The number eligible for treatment dropped from 90% to 10%
10
Young menOrange Farm2000
Carpenter et al. JAMA (2000) 283: 381-390; DHHS (2000)http://guideline.gov/content.aspx?id=36814; WHO (2002) www.who.int
Rationale for 2002 guidelines
[Only start treatment] in asymptomatic patients when the CD4 count drops below 200/L. … While beginning therapy before the CD4 cell count falls below 200/L clearly provides clinical benefits, the actual point above 200/L at which to start therapy has not been definitively determined.
WHO (2002). Scaling up Antiretroviral Therapy in Resource Limited Settings: Guidelines for a Public Health approach. Geneva, World Health Organization.
IAS (DHHS) guidelines 2012
All adults with HIV infection should be offered ART regardless of CD4 cell count, based on …data [showing] that all patients may benefit from ART …[and] that ART reduces the likelihood of HIV transmission [and] provides clinical benefits.
Thompson et al. JAMA (2012) 308: 387-402.
Ending AIDS in VietnamCan Tho Province
0
Size of each group and sub-group
HIV prevalence by risk group in Can Tho Province, Vietnam
Kato JAIDS (2013) in press
Force infection to start in FSW
HIV prevalence by risk group in Can Tho Province, Vietnam
Kato JAIDS (2013) in press
Red: Prevalence of HIV; Blue: number of people living with HIV in Can Tho, Vietnam
Kato JAIDS (2013) in press.
Risk groupSize of group
1000
800
600
400
200
0
1990 2010 2030 2050
New
infe
ctio
ns/
year
Kato JAIDS (2013) in press
HIV incidence in Can Tho, Vietnam
Current coverageCD4 350 (90%)Methadone (IDU); condoms (MSM)Annual testing, immediate treatment (80%)
The understanding that mathematical models brings is essential for good public health.But people and politicians make decisions for many reasons, most of which we don’t understand and may not even be aware of.We need to think carefully about how to persuade them of the value of our work and how to understand what it is that constrains their world and decisions.
Thank you