arv-based prevention: perspective from epidemiology & modelling tim hallett imperial college...
TRANSCRIPT
ARV-Based Prevention:Perspective from Epidemiology & Modelling
Tim HallettImperial College London
96% reduction in transmission in couples may not translate into a 96% reduction in population level HIV incidence.
Can we talk about “elimination”. Is this above or
below R0=1?
How many infections are generated by a newly-infected person before they could
be initiated on ART?
Network
ProgrammeUptake
ClinicalCare
Effectiveness and feasibility studies
Biology
Even risk Heterogenous risk0%
20%
40%
60%
80%
100%
Reduction in Incidence
“Test and Treat” intervention making different assumptions about population risk behaviours.
Some models assume this.... ... But others assume this.Dodd et al., AIDS 2010
Power et al. The Lancet, 2011
Powers et al. estimate large contribution of early HIV infection……
And that infections are generated so rapidly after infection that, elimination not possible with treatment to chronic infection only.
Questions:-Influence assumptions about sexual risk behaviours?- Influence of assumed high and variable infectiousness during early HIV infection?
Eaton et al., Forthcoming
To get a 60% reduction in incidence:
90% are treated, irrespective of CD4 cell count.
Sufficient frequency of testing such that 60% within 1 years of infection.
1% of patient drop out
87% viral suppression within 6 months of initiation.
Probability of reducing HIV incidence by >60%:
Eaton et al., Forthcoming
Drop-out rate: 1% per year
Drop-out rate: 7.5% per year
What else?
Combination Treatment and PrEP.
80% Coverage ART (CD4<200)
80% Coverage ART (half at CD4<350)
80% Coverage ART (Any CD4)
No PrEP
PrEP to 40% Young People
PrEP to 80% of Young People
PrEP to 80% of Population
80% Coverage ART (all at CD4<350)
Cremin et al., Forthcoming
80% Coverage ART (CD4<200)
No PrEP
80% Coverage ART (CD4<200)
PrEP to 80% Young People
80% Coverage ART (CD4<200)
PrEP to 80% of Population
PrEP to 40% Young People
80% Coverage ART (CD4<200)
80% Coverage ART (half at CD4<350)
No PrEP
80% Coverage ART (half at CD4<350)
PrEP to 80% Young People
80% Coverage ART (half at CD4<350)
PrEP to 80% of Population
PrEP to 40% Young People
80% Coverage ART (half at CD4<350)
80% Coverage ART (all at CD4<350)
No PrEP
80% Coverage ART (all at CD4<350)
PrEP to 80% Young People
80% Coverage ART (all at CD4<350)
PrEP to 80% of Population
PrEP to 40% Young People
80% Coverage ART (all at CD4<350)
80% Coverage ART(Any CD4)
No PrEP
80% Coverage ART(Any CD4)
PrEP to 80% Young People
80% Coverage ART(Any CD4)
PrEP to 80% of Population
PrEP to 40% Young People
80% Coverage ART(Any CD4)
Cremin et al., Forthcoming
0
20
40
60
80
100
0 2 4 6 8 10 12
% R
educ
tion
in H
IV in
cide
nce
in 2
023
Total cost 2013 - 2023 (US $) Billions
ART only ART + PrEP to young people
ART + PrEP to any age.
ART <200
ART <350
Early ART
Early ART + PrEP to young people
Early ART + PrEP to any age
ART < 350 + PrEP to 80% young people
KZN, South Africa
0
20
40
60
80
100
0 2 4 6 8 10 12
% R
educ
tion
in H
IV in
cide
nce
in 2
023
Total cost 2013 - 2023 (US $) Billions
ART only ART + PrEP to young people
ART + PrEP to any age.
ART <200
ART <350
Early ART
ART <350 + PrEP to young people
KZN, South Africa
• The potential questions about the impact of treatment on prevention are MANY.
• Impact will depend on myriad factors, so it will be have to be an INTERDISCIPLINARY research effort.
• New data will keep on moving us from “What If..?” speculation to a “What now?” precise set of questions.
• Not a silver bullet, so what are the smart COMBINATIONS?
Imperial College London
Geoff Garnett,
Simon Gregson
Ide Cremin,
Annick Bourquez,
Gabriela Gomez,
Jeff Eaton,
Pete Dodd,
John Williams,
Christophe Fraser
UNAID & WHO
Bernhard Schwartlander
Peter Ghys
Kevin O’Reilly
Thanks to...University of Washington
Connie Celum,
Ramzi Alsallaq,
Jared Baeten,
Jim Hughes,
Weill-Cornell
Laith Abu-Raddad
Hiam Chemaitelly
LSHTM
Peter Piot
Georgetown
Mark Dybul
Funded by: The Wellcome Trust, Bill & Melinda Gates Foundation, NIH