The epidemiology of herpes simplex virus type 2 in sub-Saharan Africa: systematic review, meta-analyses, and meta-regressions

Abstract

BackgroundHerpes simplex virus type 2 (HSV-2) infection is a prevalent sexually transmitted infection with a sizable disease burden that is highest in sub-Saharan Africa. This study aimed to characterize HSV-2 epidemiology in this region.MethodsCochrane and PRISMA guidelines were followed to systematically review, synthesize, and report HSV-2 related findings. Meta-analyses and meta-regressions were conducted.FindingsFrom 218 relevant publications, 451 overall outcome measures and 869 stratified measures were extracted. Pooled incidence rates ranged between 2.4-19.4 per 100 person-years across populations. Pooled seroprevalence was lowest at 37.3% (95% confidence interval (CI): 34.9-39.7%) in general populations and high in female sex workers and HIV positive individuals at 62.5% (95% CI: 54.8-70.0%) and 71.3% (95% CI: 66.5-75.9%), respectively. In general populations, pooled seroprevalence increased steadily with age. Compared to women, men had a lower seroprevalence with an adjusted risk ratio (ARR) of 0.61 (95% CI: 0.56-0.67).Seroprevalence decreased in recent decades with an ARR of 0.98 (95% CI: 0.97-0.99) per year. Seroprevalence was highest in Eastern and Southern Africa. Pooled HSV-2 proportion in genital ulcer disease was 50.7% (95% CI: 44.7-56.8%) and in genital herpes it was 97.3% (95% CI: 84.4-100%).InterpretationSeroprevalence is declining by 2% per year, but a third of the population is infected. Age and geography play profound roles in HSV-2 epidemiology. Temporal declines and geographic distribution of HSV-2 seroprevalence mirror that of HIV prevalence, suggesting sexual risk behavior has been declining for three decades. HSV-2 is the etiological cause of half of GUD and nearly all genital herpes cases.FundingThis work was supported by pilot funding from the Biomedical Research Program at Weill Cornell Medicine in Qatar and by the Qatar National Research Fund [NPRP 9-040-3-008].

Epidemiology of herpes simplex virus type 2 in Asia: A systematic review, meta-analysis, and meta-regression

“…This study provided a thorough, systematic investigation of HSV-2 epidemiology in Asia. HSV-2 seroprevalence was estimated at 12% of the general population of this region, lower than that estimated recently in Africa at 37% 24 and in Latin America and the Caribbean (LAC) at 21%. 39 Remarkably, seroprevalence has been declining at about 2% per year over the last three decades, just as recently found in Africa, 24 LAC, 39 and the United States of America.…”

“…HSV-2 seroprevalence was estimated at 12% of the general population of this region, lower than that estimated recently in Africa at 37% 24 and in Latin America and the Caribbean (LAC) at 21%. 39 Remarkably, seroprevalence has been declining at about 2% per year over the last three decades, just as recently found in Africa, 24 LAC, 39 and the United States of America. [40] , [41] , [42] , [43] Such similar declines in different regions may suggest that risky sex has declined since recognition of the HIV epidemic, [44] , [45] , [46] , [47] increased STI awareness, 48 greater access to HIV/STI services, 22 , 49 and/or possibly socio-economic changes that affected the structure of sexual networks leading to lower infection incidence.…”

“…Curiously, HSV-2 seems more significant in genital herpes among men than women ( Table 4 ), a finding that may reflect the relative ease of clinically diagnosing this condition in men compared to women. Results confirmed key attributes of HSV-2 epidemiology that appear across Asia, Africa, 24 and LAC. 39 Seroprevalence varied immensely by population sexual-risk classification, 24 , 39 and this heterogeneity explained nearly half the seroprevalence variation across studies ( Table 3 ).…”

“…HSV-2 persists as the etiological cause of nearly half (48%) of GUD cases, similar to Africa at 51% 24 and LAC at 41%. 39 The disproportional role of HSV-2 infection in this disease outcome may persist for decades despite its declining seroprevalence, as other causes, such as syphilis, 53 may also be declining concurrently.…”

“…Methodology of this study was adapted from our published systematic reviews characterizing epidemiology of HSV-2 in Africa 24 and epidemiology of HSV-1 in Asia 25 ; therefore, no study protocol was registered in PROSPERO.…”