The risk of contracting HIV was almost three to five times higher among people infected with herpes simplex virus type 2 (HSV-2), in a systematic review and meta-analysis.
The analysis of 57 longitudinal studies found that the adjusted relative risk (RR) of HIV incidence after exposure to HSV-2 infection at baseline (“prevalent infection”) was 2.7 and was 4.7 after exposure to HSV-2 infection during follow-up (“incident infection”). The studies, mostly conducted in Africa, were found in PubMed, MEDLINE, and Embase publications from Jan. 1, 2003, to May 25, 2017; the analysis was published online on Aug. 23 ().
“The greater cofactor effect for incident HSV-2 infection than for prevalent HSV-2 infection might be because newly acquired HSV-2 infection is associated with an increased frequency and severity of genital ulceration, viral shedding, and inflammation in the genital tract, symptoms and manifestations that decrease with time after infection,” according to, of the University of Bristol (England), and , of Imperial College London (England) and their coauthors.
Associations still were significant but lower in higher-risk populations, such as female sex workers and their clients, men who have sex with men, and serodiscordant couples, the researchers said. For those with prevalent HSV-2, the adjusted RR of contracting HIV was 1.7 (95% confidence interval, 1.4-2.1), compared with 2.9 for those with incident HSV-2 infection (95% CI, 1.7-5.0).
“Quantifying the effect of HSV-2 infection on HIV acquisition has important public health implications, particularly in high-prevalence settings where coinfection is common, because prevention of HSV-2 infection ... might indirectly prevent HIV infection,” the authors wrote. “Knowledge of this association informs the advice and information given to individuals diagnosed with genital herpes, who might be at increased risk of acquiring HIV.”
The study was funded by the World Health Organization. Dr. Looker reported personal fees from the WHO. Dr. Elmes reported grants from the National Institutes of Health and the Wellcome Trust outside of this study. Two authors reported financial support from Aquarius Population Health and other support from WHO and NIH; the three remaining authors had no disclosures.