The potential impact of a hepatitis C vaccine for people who inject drugs: is a vaccine needed in the age of direct-acting antivirals?

Stone, Jack, Martin, Natasha K., Hickman, Matthew, Hellard, Margaret, Scott, Nick, McBryde, Emma, Drummer, Heidi, and Vickerman, Peter (2016) The potential impact of a hepatitis C vaccine for people who inject drugs: is a vaccine needed in the age of direct-acting antivirals? PLoS ONE, 11 (5). e0156213. pp. 1-19.

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Abstract

Background and Aims: The advent of highly effective hepatitis C (HCV) treatments has questioned the need for a vaccine to control HCV amongst people who inject drugs (PWID). However, high treatment costs and ongoing reinfection risk suggest it could still play a role. We compared the impact of HCV vaccination amongst PWID against providing HCV treatment.

Methods: Dynamic HCV vaccination and treatment models among PWID were used to determine the vaccination and treatment rates required to reduce chronic HCV prevalence or incidence in the UK over 20 or 40 years. Projections considered a low (50% protection for 5 years), moderate (70% protection for 10 years) or high (90% protection for 20 years) efficacy vaccine. Sensitivities to various parameters were examined.

Results: To halve chronic HCV prevalence over 40 years, the low, moderate and high efficacy vaccines required annual vaccination rates (coverage after 20 years) of 162 (72%), 77 (56%) and 44 (38%) per 1000 PWID, respectively. These vaccination rates were 16, 7.6 and 4.4 times greater than corresponding treatment rates. To halve prevalence over 20 years nearly doubled these vaccination rates (moderate and high efficacy vaccines only) and the vaccination-to-treatment ratio increased by 20%. For all scenarios considered, required annual vaccination rates and vaccination-to-treatment ratios were at least a third lower to reduce incidence than prevalence. Baseline HCV prevalence had little effect on the vaccine's impact on prevalence or incidence, but substantially affected the vaccination-to-treatment ratios. Behavioural risk heterogeneity only had an effect if we assumed no transitions between high and low risk states and vaccinations were targeted or if PWID were high risk for their first year.

Conclusions: Achievable coverage levels of a low efficacy prophylactic HCV vaccine could greatly reduce HCV transmission amongst PWID. Current high treatment costs ensure vaccination could still be an important intervention option.

Item ID: 44842
Item Type: Article (Research - C1)
ISSN: 1932-6203
Additional Information:

© 2016 Stone et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

https://creativecommons.org/licenses/by/4.0/

Funders: Engineering and Physical Sciences Research Council (EPSRC), National Institute for Health Research (NIHR), National Institute for Drug Abuse (NIDA), University of California San Diego Center for AIDS Research (CFAR), National Institutes of Health (NIH), Burnet Institute (BI)
Projects and Grants: NIDA R01 DA037773-01A1, NIH P30 AI036214
Date Deposited: 11 Aug 2016 23:44
FoR Codes: 32 BIOMEDICAL AND CLINICAL SCIENCES > 3202 Clinical sciences > 320211 Infectious diseases @ 34%
42 HEALTH SCIENCES > 4206 Public health > 420699 Public health not elsewhere classified @ 33%
44 HUMAN SOCIETY > 4407 Policy and administration > 440706 Health policy @ 33%
SEO Codes: 92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920109 Infectious Diseases @ 50%
92 HEALTH > 9202 Health and Support Services > 920206 Health Policy Economic Outcomes @ 50%
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