As a result of increased opioid use, worldwide nearly one in six people are living with human immunodeficiency virus (HIV) and more than half have been exposed to hepatitis C virus (HCV), and one in ten have active Hepatitis B virus (HBV), researchers have found.

According to the study, published in the journal The Lancet Global Health, globally an estimated 15.6 million people injected drugs, in the age group 15-64 years, in 2015. Out of these, 18 per cent are living with HIV infection and 52 per cent test positive for hepatitis C antibody.

The main drug was either an opioid (heroin or other opioid) or stimulant (amphetamine or cocaine), the researchers said.

Further, sharing of equipment used for injecting drug use was found as the substantial cause of disease burden and a contributor to blood-borne virus transmission.

“Across all countries a substantial number of people who inject drugs are living with HIV or HCV and are exposed to multiple adverse risk environments that increase health harms,” said lead author Louisa Degenhardt, Professor at the University of New South Wales in Australia.

In the study, the team found evidence of injected drug use in 179 countries that contain 99 per cent of the world’s population aged 15-64 years, up from 148 countries in 2007.

The largest use of injected drugs were found in east and southeast Asia (4.0 million, 3.0-5.0 million), eastern Europe (3.0 million, 1.7-5.0 million), and North America (2.6 million, 1.5-4.4 million).

The provision of programmes to prevent the spread of HIV and HCV is inadequate in many countries around the world and presents a critical public health problem, the researchers rued.

Just over half (52 per cent) of the countries had needle syringe programmes and medical treatment to encourage reductions in injecting, while opioid substitution therapy was available in less than half of all countries (48 per cent).

Thus “scaling up of interventions remains a crucial priority for halting the HIV and HCV epidemics”, the researchers noted.