Background
Widely
access to interferon-free direct-acting antiviral regimens (IFN-free DAA) is
poised to dramatically change the impact of the HCV epidemic among people who
inject drugs (PWID). We evaluated the long-term effect of increasing HCV
testing, treatment and engagement into harm-reduction activities, focused on
active PWID, on the HCV epidemic in British Columbia (BC), Canada.
Methods
We
built a compartmental model of HCV disease transmission stratified by disease
progression, transmission risk, and fibrosis level. We explored the effect of:
(1) Increasing treatment rates from 8 to 20, 40 and 80 per 1000 infected PWID/year;
(2) Increasing treatment eligibility based on fibrosis level; (3) Maximizing
the effect of testing by performing it immediately upon ending the acute phase;
(4) Increasing access to harm-reduction activities to reduce the risk of
re-infection; (5) Different HCV antiviral regimens on the Control Reproduction
Number Rc. We assessed the impact of
these interventions on incidence, prevalence and mortality from 2016 to 2030.
Results
Of
all HCV antiviral regimens, only IFN-free DAAs offered a high chance of disease
elimination (i.e. Rc < 1), but it would be necessary to
substantially increase the current low testing and treatment rates. Assuming a
treatment rate of 80 per 1000 infected PWID per year, coupled with a high
testing rate, the incidence rate, at the end of 2030, could decrease from 92.9
per 1000 susceptible PWID per year (Status Quo) to 82.8 (by treating only PWID
with fibrosis levelF2 and
higher) or to 65.5 (by treating PWID regardless of fibrosis level). If PWID
also had access to increased harm-reduction activities, the incidence rate
further decreased to 53.1 per 1000 susceptible PWID per year. We also obtained
significant decreases in prevalence and mortality at the end of 2030.
Conclusions
The combination of increased access to HCV testing,
highly efficacious antiviral treatment and harm-reduction programs can
substantially decrease the burden of the HCV epidemic among PWID. However,
unless we increase the current levels of treatment and testing, the HCV
epidemic among PWID in BC, and in other parts of the world with similar
epidemiological background, will remain a substantial public health concern for
many years.
Below: Percent change in (A) HCV incidence rate, (B) HCV prevalence
and (C) mortality, at the end of 2030, for different testing and treatment
scale-up scenarios. Blue bars: assume that 140 per 1000 PWIDs are tested and
that 8, 20, 40 and 80 per 1000 PWID are treated for HCV per year; treatment
eligibility applies only to the chronic aware population (Ca)
with fibrosis level F2 and higher. Green bars:
assume that 140 per 1000 PWIDs are tested and that 8, 20, 40 and 80 per 1000
PWID are treated for HCV per year; treatment eligibility applies only to the
chronic aware population (Ca) with fibrosis level F0 and
higher. Gold bars: assume that PWIDs are tested immediately upon ending the
acute phase and that 8, 20, 40 and 80 per 1000 PWID are treated for HCV per
year; treatment eligibility applies both to the chronic unaware (Cu)
and aware (Ca) population with fibrosis level F0 and
higher. Note that in this case PWID do not spend time in the Cu compartment
and go straight to theCa compartment due to the testing
intervention.
Purchase full article at: http://goo.gl/sFrAag
By:
Viviane D. Lima, Ignacio Rozada, Mark Hull, Lillian Lourenco,
Bohdan Nosyk, Evan Wood, Julio S. G. Montaner
British Columbia Centre for Excellence in HIV/AIDS,
Vancouver, British Columbia, Canada
Jason Grebely
The Kirby Institute, University of New South Wales
Australia, Sydney, NSW, Australia
Mel Krajden
Public Health Microbiology and Reference Laboratory, British
Columbia Centre for Disease Control, Vancouver, British Columbia, Canada
Eric Yoshida
Division of Gastroenterology, Department of Medicine,
Faculty of Medicine, University of British Columbia, Vancouver, British
Columbia, Canada
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