NEW YORK (Reuters Health) – The global estimate of hepatitis C virus infection (HCV) is lower than previously thought, making World Health Organization targets for reducing infections and HCV-related deaths more attainable, researchers suggest.

“In 2016, the WHO introduced global targets of a 90% reduction in new HCV infections and 65% reduction in hepatitis C-related deaths by 2030,” Dr. Homie Razavi of the Center for Disease Analysis in Lafayette, Colorado, told Reuters Health by email. “However, to achieve these goals, a baseline understanding of total HCV infections at the national and global level is required.”

To update and expand a 2014 analysis based on a review of various reports published from 2000 to 2013, Dr. Razavi and his colleagues took a different approach to derive prevalence data for 100 countries.

In addition to doing a traditional systematic review, they developed country-level disease-burden models based on 6,754 HCV prevalence studies and 11,342 genotype studies published after 2013, they write in The Lancet Gastroenterology and Hepatology, online December 15.

Dr. Razavi explained, “This year, WHO reported that over one million people have been treated with highly effective hepatitis C medicines that have a 95% cure rate. Thus, using old reports without adjustment for treatment and mortality would overestimate the total number of HCV infections.”

Among all countries with a prevalence estimate, the viremic rate was available for 81 countries (82% of the world’s population), and age and sex distributions were available for 89 countries (85%). A level of validation was added through consultations with 400 country experts. The experts approved the inputs and outputs of 59 of the country models, and published data alone was used to estimate prevalence in an additional 41 countries. In countries where no data was available, the team “estimated infections based on countries in the same region,” Dr. Razavi said.

The global prevalence of viremic HCV is estimated to have been 1.0% in 2015, corresponding to 71.1 million infections. Genotypes 1 (44%) and 3 (25%) were the most common causes. The authors suggest that recent estimates of a lower prevalence of HCV in Africa, as well as increased mortality due to liver-related causes and aging, may have contributed to the reduction in infections.

Dr. Razavi observed, “Six countries (China, Pakistan, India, Egypt, Russia, and United States) account for more than half of all HCV infections globally due to a high prevalence and/or large population. Although a large number of HCV-infected individuals need to be treated in these countries, in most other countries the total number of infected cases is not as high as previous estimates. This makes elimination of HCV by 2030 more achievable.”