Seroprevalence overview
More than 80% of the studies reporting seroprevalence measures (n=429) were published after 2005 (n=352, 82.1%). Most studies used convenience sampling (n=374, 87.2%). All seroprevalence measures are summarized in Table 1 and Table 2. Most studies collected data during the 21st century (2000-2010: 42.0%; after 2010: 42.4%).
Pooled means of HSV-2 seroprevalence among overall populations was 14.9% (n=947, 95% confidence interval (CI): 13.8%-16.1%). Pooled mean HSV-2 seroprevalence was lowest at 7.8% (n=10, 95% CI: 2.6%-15.2%) among other populations, followed by 7.9% (n=256, 95% CI: 6.9%-8.8%) among the general population, 16.7% (n=16, 95% CI: 12.7%-21.1%) among intermediate-risk populations, 23.1% (n=73, 95% CI: 20.5%-25.8%) among STI clinic attendees and symptomatic populations, and 26.0% (n=14, 95% CI: 20.0%-32.4%) among people living with HIV (PLWH) and their couples, and 32.1% (n=80, 95% CI: 27.8%-36.5%) among those at high risk. Across all populations except for HIV-positive and individuals in HIV-discordant couples, women had higher pooled mean seroprevalence than men (Table 1 ).
Table 2 shows stratified subpopulations in the general populations and their range of seroprevalence. Pooled mean seroprevalence was higher in the Northeast region at 12.4% (n=18, 95% CI: 7.8-17.9%), followed by the Central-southern region at 10.5% (n=126, 95% CI: 8.4-12.7%). The pooled mean seroprevalence increased with age from the age group 20-29 years. Pooled mean seroprevalence was 5.6% (95% CI: 4.0-7.3%) among 20-29-year-olds (n=74), followed by 8.2% (95% CI: 6.0-10.6%) among 30-39-year-olds (n=50), 8.9% (95% CI: 5.1%%-13.5%) in those aged 40-49 years (n=60), 15.3% (95% CI: 12.0-19.0%) in those aged 50-59 years (n=14), and 20.0% (95% CI: 9.9-32.3%) in those aged ≥60 years (n=9). Pooled mean seroprevalence decreased with the year of data collection and year of publication. Pooled mean seroprevalence was 15.1% (95% CI: 8.3-23.4%) for data collected in 2000 and earlier (n=30), followed by 6.9% (95% CI: 5.6-8.3%) during 2001-2010 (n=205) and 6.7% (95% CI: 5.7-7.8%) after 2010 (n=231). For year of publication, pooled mean seroprevalence was 10.7% (95% CI: 7.2-14.7%) in 2005 and earlier (n=71), followed by 8.1% (95% CI: 6.7-9.6%) during 2006-2015 (n=258) and 6.5% (95% CI: 5.6-7.4%) after 2015 (n=175).
High and significant heterogeneity was found between studies (p-value <0.001, I2>50%). Forest plots of different meta-analyses are displayed in Figure S1-S2.
The heatmap in Figure 2 shows that HSV-2 seroprevalence varied across different provinces in China, with higher HSV-2 seroprevalence in Jilin, Liaoning, and Yunnan Provinces.