Prevalence of herpes simplex virus 2 among MSM in Mainland China: a systematic review and meta-synthesis
Authors: Shi Mingming , Zhang Xiao , Chen Mengqing 
Published: October 2022

Abstract
Background
As one of the most prolific sexually transmitted infections (STIs) in the world, Herpes Simplex Virus Type 2 (HSV-2) is one of the primary causes of genital ulcers. In addition, HSV-2 infection multiplies the risk of acquiring HIV. Men who have sex with men (MSM) are at particularly high risk of contracting both diseases. Unfortunately, little information is available with regarding to the comprehensive prevalence of HSV-2 among MSM in mainland China. The objective of this manuscript was to determine the composite prevalence of HSV-2 among MSM in mainland China via systematic review and meta-synthesis.

Methods
We systematically searched PubMed, Embase, Chinese National Knowledge Infrastructure, WanFang Database for Chinese Periodicals, and the VIP Database for Chinese Technical Periodicals for relevant articles published from the database’s inception to 28 April 2022 that reported data on the prevalence of HSV-2 within the MSM population in mainland China. We considered publications to be eligible for inclusion if they satisfied these conditions: (1) publication participants were MSM in China mainland. Studies were excluded if participants were exclusively all HIV-positive MSM, all HIV-negative MSM, injection-drug users, or MSM sex workers. These studies would have introduced selection bias and skewed pooled prevalence estimates higher or lower; (2) proportion of HSV-2 virus among MSM in China mainland were reported; (3) HSV-2 diagnosis was conducted in a laboratory based on a strict type-specific glycoprotein-G based assays diagnostic method or PCR method; and (4) had a sample size over 20. Exclusion criteria included: (1) not being an original manuscript, such as a review article; (2) being a guideline, correspondence, and/or conference abstract; (3) the publication population did not reside in China mainland when the study was carried out; and (4) if the same epidemiological data were printed in both English and Chinese journals, English articles were preferred. We assessed the risk of bias in each individual publication using the modified quality assessment tool for systematic reviews of observational publications (QATSO). This meta-analysis was conducted by using R software. Due to extensive heterogeneity between various publications, we employed a random effect model to calculate the composite prevalence and corresponding 95% confidence intervals. We then conducted meta-regression to investigate the potential causes of observed heterogeneity. Lastly, we employed subgroup analysis based on characteristics of studies to compare the prevalence estimates across the groups. Publication bias was evaluated by funnel plot, Begg’s test and Egger’s test. Sensitivity analysis was also performed by removing each single study separately.

Results
This study included 31 articles (9 published in English and 22 in Chinese) in our meta-synthesis. The pooled prevalence of HSV-2 among MSM in China mainland was 0.094 (95%CI:0.074 to 0.116). Prevalence of HSV-2 among MSM in Southwest China was higher than other regions, prevalence of HSV-2 among MSM that recruited from VCT (Voluntary Counseling and Testing) was lower than other ways, respectively. Compared to 2000–2010, the prevalence of HSV-2 among MSM in mainland China showed a downward trend during 2011–2020, however, the difference was not statistically significant .

Conclusion
Prevalence of HSV-2 among MSM in China mainland is high, around 0.094. It indicated HSV-2 needed to be screening for MSM population among China mainland and proper actions should be taken to curve the trend of HSV-2 among MSM in China.
Trial registration CRD42020180361.