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

Background: This study characterized the epidemiology of herpes simplex virus type 2 (HSV-2) infection in Canada, Australia, and New Zealand. Methods: Cochrane and PRISMA guidelines were followed to systematically review, synthesize, and report HSV2-related data up to January 21, 2021. Meta-analyses and meta-regressions were performed. Results: In Canada, pooled mean seroprevalence was 10.0% (95% confidence interval [CI], 7.8-12.4%) among general populations, 44.5% (95% CI, 20.0-70.5%) among sexually transmitted infection clinic attendees and symptomatic populations, and 60.7% (95% CI, 49.8-71.1%) among human immunodeficiency virus (HIV)-positive individuals and individuals in HIV-discordant couples. In Australia and New Zealand, combined, pooled mean seroprevalence was 15.4% (95% CI, 9.6-22.2%) among general populations, 27.8% (95% CI, 12.0-47.2%) among men who have sex with men, and 37.2% (95% CI, 23.7-51.8%) among sexually transmitted infection clinic attendees and symptomatic populations. Men had 0.64-fold (95% CI, 0.47-0.86) lower seroprevalence compared with women. No evidence was found for a decline in seroprevalence over time. Pooled mean proportion of HSV-2 isolation in laboratory-confumed genital herpes was 62.1% (95% CI, 53.8-70.1%) in Canada and 71.9% (95% CI, 64.2-78.9%) in Australia and New Zealand. Proportion of HSV-2 isolation in genital herpes declined by 0.98-fold (95% CI, 0.97-0.99) per year. Pooled mean proportion of HSV-2 isolation in genital ulcer disease was 17.4% (95% CI, 4.0-37.1%) in these countries. Conclusions: Over 10% of adults in these countries are infected, with no evidence for declining seroprevalence, unlike other global regions. Over 60% of genital herpes cases are caused by HSV-2 in these countries, yet HSV-2's role is declining by 2% per year.