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  International AIDS Conference
Durban, South Africa
July 18-22 2016
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HCV Coinfection Not Tied to Higher HIV Load in Meta-Analysis
  21st International AIDS Conference (AIDS 2016), July 18-22, 2016, Durban, South Africa
Mark Mascolini
Meta-analysis of published articles and meeting abstracts did not find that untreated HCV coinfection results in higher HIV load [1]. Nor did treatment of HCV affect HIV load. The findings are particularly surprising because other coinfections do clearly lead to higher viral loads in people with HIV infection.
Researchers at the University of Washington and collaborators in London noted that people coinfected with HCV and HIV have higher HCV loads and run a greater risk of cirrhosis or liver failure than people without HIV. But the impact of HCV infection on HIV load is not well understood. Coinfection with herpes simplex virus type 2, malaria, or tuberculosis clearly can lead to higher HIV loads and so bolster the risk of HIV transmission.
To assess the impact of HCV on HIV load, these investigators conducted a systematic review and meta-analysis. They searched PubMed and Embase for articles and scoured meeting abstracts presented through February 2015 that address the impact of (1) untreated HCV infection on HIV viral load and (2) treated HCV infection on HIV load. They followed Cochrane Collaboration guidelines to conduct the review and PRISMA guidelines to report results.
Screening 3337 articles and abstracts yielded 16 studies for analysis. Most studies took place in Western Europe or North America, and three studies took place in China or Taiwan. Numbers of participants ranged from 8 to 606, and most studies relied on HCV antibody testing without HCV RNA assessment to classify participants as HCV-positive.
Only four studies found strong evidence of an association between HCV/HIV coinfection and HIV load, and all four found higher HIV loads in people without HCV. Two studies addressed whether treating HCV infection (with interferon/ribavirin) led to lower HIV loads. Neither study found that HCV therapy affects HIV load.
The researchers pointed out one limitation of their analysis: Reliance of HCV antibody testing alone to identify HCV infection in most studies could mean those studies included people who had cleared HCV infection. But with that caveat in mind, they say their results stand in "striking contrast" to analyses of other pathogens linked to higher HIV load, probably through inflammatory-mediated mechanisms. The researchers suggested their study "highlights the opportunity to explore the different mechanisms of interaction between HIV and HCV compared with HIV and other pathogens that result in persistent or recurrent systemic infections."
1. Ross J, Petersdorf N, Weiss H, et al. Systematic review and meta-analysis of HCV infection and HIV viral load: insights into epidemiologic synergy. 21st International AIDS Conference (AIDS 2016). July 18-22, 2016. Durban, South Africa. Abstract THPEC104.