Regional Differences In The Association Between Hiv And Hsv-2 Prevalence: Implications For Hiv Epidemic Potential

Abstract

ABSTRACT Background and Objective HIV and herpes simplex virus type-2 (HSV-2) are sexually transmitted infections, with HSV-2 being nearly 10 times as infectious as HIV. HSV-2 prevalence has been established as an objective biomarker and a proxy measure of sexual risk behavior. HIV epidemics appear to be emerging in the Middle East and North Africa (MENA) region, but the time course and future size of these epidemics are still unknown. We assessed HIV epidemic potential across regions using the association between HSV-2 and HIV prevalence, and based on a global systematic review of HIV and HSV-2 prevalence and meta-analyses. Methods Sources of data were PubMed and Embase databases, and country-level reports. Data on the prevalence of HIV (PHIV) and of HSV-2 (PHSV2) in the same population were extracted from eligible studies. Our analysis included all population groups except adolescents and injecting drug users, where the dominant mode of HIV transmission was not sexual. Studies with sample sizes of less than 50 were excluded. Odds ratios were calculated as (PHSV2/ (1- PHSV2)) / (PHIV/ (1- PHIV)), and relative risks as (PHSV2/ PHIV). Meta-analyses were conducted incorporating the inverse variance method and using a random-effects model to pool summary estimates of odds ratios and relative risks in different geographical regions. Results The meta-analysis included 662 study measures with a total population of 590,220 individuals from 67 countries. The pooled odds ratio of HSV-2 prevalence relative to HIV prevalence was low in Sub-Saharan Africa, Asia, and North America/West Europe, 6.0 (95% CI 5.5-6.5), 10.4 (95% CI 9.2- 11.8), and 13.0 (95% CI 9.9- 17.8), respectively. We found high odds ratios in East Europe 73.6 (95% CI 32.8-165.5), MENA 38.0 (95% CI 15.2-95.0), and Latin America 30.4 (95% CI 22.4-41.4). The pooled estimates of relative risks followed the same pattern as the odds ratios across all regions. Discussion The small odds ratios in sub-Saharan Africa, Asia, and North America/West Europe suggest established HIV epidemics that have likely reached saturation. Meanwhile, the large odds ratios in MENA, East Europe, and Latin America, suggest emerging HIV epidemics that have not yet reached their epidemic potential. These results corroborate recent data about the trend of HIV epidemics in these regions. The findings are of concern for MENA as they suggest that the HIV epidemics are likely to grow within this decade and the next one. HIV response in MENA needs to be expanded through bio-behavioral surveillance, voluntary counseling, testing, and treatment services, and focus on HIV prevention.