An estimated 2.3 million people living with HIV are co-infected with hepatitis C virus (HCV) globally, a new study has found.
Of these 2.3 million, more than half, or 1.3 million, are people who inject drugs (PWID), researchers from University of Bristol and the London School of Hygiene & Tropical Medicine said.
HIV and HCV infections are major global public health problems, with overlapping modes of transmission and affected populations. Globally, there are 37 million people infected with HIV, and around 115 million people with chronic HCV infection.
The study systematically reviewed 783 medical studies from worldwide sources to build the first global estimates on the prevalence of HIV/HCV co-infection (measured by HCV antibody) as a public health problem.
"The study shows that not only are people with HIV at much higher risk of HCV infection, groups such as people who inject drugs have extremely high prevalence of HCV infection - over 80 per cent," said Philippa Easterbrook from World Health Organisation's Global Hepatitis Programme which commissioned the study.
"There is a need to scale-up routine testing to diagnose HCV infection in HIV programmes worldwide, especially among high-risk groups, as the first step towards accessing the new, highly curative HCV treatments," said Easterbrook.
"This study shows how important injecting drug use is in driving the epidemic of HCV in people with HIV infection, especially in eastern European and central Asian countries," said Peter Vickerman from University of Bristol.
"It also shows the need to scale up prevention interventions, such as needle and syringe programmes and opioid substitution therapy, as well as access to HIV and HCV treatment, to reduce morbidity and new infections," he added.
The study focusses on prevalence of HCV antibodies that measures exposure to HCV but not active infection. Measuring the presence of active virus and the need for treatment requires an additional more costly viral test, which very few of the reviewed studies had done.
Around 20-30 per cent of people exposed to HCV and found positive with antibody will clear the virus.
The study shows the greatest burden of HIV/HCV coinfection in Eastern Europe and central Asia, where there are an estimated 607,700 cases (27 per cent of all cases), particularly among PWID.
The sub-Saharan African region accounts for 19 per cent of all cases, with 429,600 cases, due to high burdens of HIV.
The findings were published in The Lancet Infectious Diseases.
