An estimated 30% of new global HIV infections are driven by herpes simplex virus-2 (HSV-2), otherwise known as genital herpes, aidsmap reports. The researchers behind this finding suggest that efforts to treat and prevent herpes could help reduce the spread of HIV around the world.
Katherine Looker, PhD, of Bristol University Medical School, led a research team that analyzed global epidemiological data from 2016 to estimate the proportion of HIV cases that were attributable to genital herpes, taking into account other risk factors.
Genital herpes is extremely common; an estimated 420 million people worldwide are living with the lifelong sexually transmitted infection. The STI has the highest prevalence rate in Africa, where some 31% of adults are infected.
Herpes increases the risk of HIV acquisition because herpes ulcers provide a direct route through which HIV can enter the body. Additionally, herpes spurs the activation of T cells and dendritic cells and draws them to the site of infection; these immune cells are targets of HIV.
The research, the findings of which were published in The Lancet Infectious Diseases, built upon a 2017 analysis in which investigators conducted a meta-analysis of 55 prospective studies and found that people with HSV-2 infection have a threefold higher risk of acquiring HIV compared with people without herpes. Recently acquired HSV-2 is associated with a fourfold increased risk of HIV, the study authors estimated.
Among 15- to 49-year-olds, there were an estimated 1.4 million cases of sexually acquired HIV in 2016. According to the study authors’ mathematical modeling, 420,000 of those infections, or 30%, were driven by HSV-2.
Africa had the highest rate of HIV transmission attributable to HSV-2, at 37%, followed by the Americas, at 21%. In other regions of the world, this figure ranged between 11% and 13%.
Thirty-six percent of new HIV cases among men and 26% of new cases among women were attributable to herpes, as were 32% of cases among those 25 to 49 years old and 23% of cases among 15- to 24-year-olds.
Twenty-seven percent of new HIV cases among female sex workers and one in five new cases among men who have sex with men were driven by HSV-2.
“New preventive interventions against HSV-2 infection could not only improve the quality of life of millions of people by reducing the prevalence of herpetic genital ulcer disease but could also have an additional, indirect effect on HIV transmission,” the study authors concluded.
To read the aidsmap article, click here.
To read the study, click here.