Role of saliva use during masturbation in the transmission of Chlamydia trachomatis in men who have sex with men

Association between saliva use for masturbation and urethral gonorrhoea in men who have sex with men: A cross-sectional study

OBJECTIVES

The saliva of individuals with oropharyngeal gonorrhoea can contain viable Neisseria gonorrhoeae. This study examined if using saliva as a lubricant for masturbation is a risk factor for urethral gonorrhoea among men who have sex with men (MSM).

METHODS

In this cross-sectional study, MSM aged ≥18 years attending the Melbourne Sexual Health Centre between February 2021 and December 2023 were surveyed. Data were collected on sexual activities in the past 7 days, including receiving fellatio, condomless insertive anal sex, docking, and using saliva for masturbation. Multivariable logistic regression examined associations between these exposures and urethral gonorrhoea.

RESULTS

The median age of the 3114 men was 32 (IQR: 27-40), with 4.7% (n = 145) testing positive for urethral gonorrhoea. Urethral gonorrhoea was independently associated with an increasing number of partners for condomless insertive anal sex (P < 0.001). It was not significantly associated with receiving fellatio (P = 0.613), docking (P = 0.207), or using saliva for masturbation (P = 0.117). However, of the 110 men who only used saliva for masturbation, two (1.8%) had urethral gonorrhoea, and one (0.9%) had both urethral and oropharyngeal gonorrhoea.

CONCLUSION

Condomless insertive anal sex is the leading risk factor for urethral gonorrhoea and not using saliva as a lubricant for masturbation.

Modelling the potential role of saliva use during masturbation in the transmission of Neisseria gonorrhoeae at multiple anatomical sites

Background Neisseria gonorrhoeae can be cultured from saliva in men with pharyngeal gonorrhoea and could theoretically be transmitted from the pharynx to the urethra when saliva is used as a lubricant for masturbation. In this work, we proposed that saliva use during masturbation may be a potential transmission route of gonorrhoea. Methods We analysed the transmission of Neisseria gonorrhoeae at the oropharynx, urethra and anorectum with mathematical models among men who have sex with men using data from six different studies. Model 1 included transmission routes (oral sex, anal sex, rimming, kissing, and three sequential sex practices). In Model 2, we added saliva use during solo masturbation and mutual masturbation to model 1. Results Model 2 could replicate single site infection at the oropharynx, urethra and anorectum and multi-site infection across six different datasets. However, the calibration of Model 2 was not significantly different from Model 1 across four datasets. Model 2 generated an incidence of gonorrhoea from masturbation of between 5.2% (95% CI: 3.2-10.1) to 10.6% (95% CI: 5.8-17.3) across six data sets. Model 2 also estimated that about one in four cases of urethral gonorrhoea might arise from solo masturbation and mutual masturbation. Conclusions Our models raise the possibility that saliva use during masturbation may play a role in transmitting gonorrhoea. This is an important area to explore because it contributes to the knowledge base about gonorrhoea transmission.