Epidemiology of herpes simplex virus type 2 in sub-Saharan Africa: Systematic review, meta-analyses, and meta-regressions

Abstract

Background: Herpes 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. Methods: Cochrane and PRISMA guidelines were followed to systematically review, synthesize, and report HSV-2 related findings up to August 23, 2020. Meta-analyses and meta-regressions were conducted. Findings: From 218 relevant publications, 451 overall outcome measures and 869 stratified measures were extracted. Pooled incidence rates ranged between 2.4À19.4 per 100 person-years across populations. Pooled seroprevalence was lowest at 37.3% (95% confidence interval (CI): 34.9À39.7%) in general populations and high in female sex workers and HIV-positive individuals at 62.5% (95% CI: 54.8À70.0%) and 71.3% (95% CI: 66.5À75.9%), 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: 0.56À0.67). Seroprevalence has decreased in recent decades with an ARR of 0.98 (95% CI: 0.97À0.99) per year. Seroprevalence was highest in Eastern and Southern Africa. Pooled HSV-2 proportion in genital ulcer disease was 50.7% (95% CI: 44.7À56.8%) and in genital herpes it was 97.3% (95% CI: 84.4À100%). Interpretation: Seroprevalence 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 genital ulcer disease and nearly all genital herpes cases with limited role for HSV-1.

Epidemiology of Herpes Simplex Virus Type 2 in Canada, Australia, and New Zealand: Systematic Review, Meta-Analyses, and Meta-Regressions

“…Unlike as in Africa, 21 Asia, 20 LAC, 22 and the United States, 42s–45s there was no evidence for declining HSV-2 seroprevalence in these countries. It is not known whether this lack of decline compared with other world regions could be a consequence of recent migration into these countries from countries with higher seroprevalence than in these countries.…”

“…48s–52s,58s Herpes simplex virus type 2 genital herpes seems to affect men more than women (Table 5), but this may reflect the ease of clinically diagnosing this condition in men compared with women and/or disproportional contribution of genital herpes among MSM. 59s Herpes simplex virus type 2 seems to play a minor role in GUD, at only 17% (Table 4), lower than that found in Africa at 51%, 21 Asia at 48%, 20 and LAC at 41% 22 . However, only 5 GUD studies were identified in these countries; thus, they may not be representative of the true contribution of HSV-2 to GUD in these countries.…”

“…42s-45s It appears thus that HSV-2 seroprevalence in Canada has been lower than that in the United States, perhaps because Canada was less affected by the cohort effect of high incidence between 1960 and mid-1980s that was described recently for the United States. 44s Unlike as in Africa, 21 Asia, 20 LAC, 22 and the United States, 42s-45s there was no evidence for declining HSV-2 seroprevalence in these countries. It is not known whether this lack of decline compared with other world regions could be a consequence of recent migration into these countries from countries with higher seroprevalence than in these countries.…”

“…These findings support the existence of generic patterns in the global epidemiology of HSV-2 infection. Just as in Africa, 21 Asia, 20 and LAC, 22 seroprevalence increased steadily with age and varied immensely by population sexual-risk classification (Table 3 ). Age and risk group alone explained over half of the seroprevalence variation across studies (Table 3 ).…”

“…The study was conducted to complement a series of studies for other global regions, as part of a project intended to characterize the global epidemiology of HSV-2 infection. [20][21][22]…”