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06 Sep 2023

Should we change how often men who have sex with men are screened for STI?

Researchers from the Doherty Institute and the Melbourne School of Population and Global Health at the University of Melbourne are proposing a review of the frequency for asymptomatic chlamydia and gonorrhoea testing in men who have sex with men (MSM). This frequency, in their view, is leading to high levels of broad-spectrum antibiotic use which may be contributing to an increased risk of antibiotic resistance.  

In a review, which sought to outline the harms and benefits of the frequent screening of chlamydia and gonorrhoea in MSM published in The Lancet Infectious Diseases, the researchers suggest that there is limited evidence that frequent screening reduces the number of people living with these sexually transmitted infections (STIs) in the community. This approach is supported by a recent US Preventive Service Task Force systematic review which concluded there was insufficient evidence to assess the balance of benefits and harms of screening for chlamydia and gonorrhoea in men.  

Current Australian guidelines, recommend that MSM in high-income settings undertake asymptomatic screening for chlamydia and gonorrhoea infection every 3-6 months. This includes those taking pre-exposure prophylaxis (PrEP) and those with HIV infection if risk behaviours persist or if they or their sex partners have multiple partners.  

The Royal Melbourne’s Hospital’s Dr Eloise Williams, Clinical Microbiologist and Infectious Diseases Physician in the Victorian Infectious Disease Reference Laboratory (VIDRL) at the Doherty Institute and co-author of the paper says, “With new research suggesting that the increased risk of antibiotic-resistant sexually transmitted superbugs may be related to frequent testing and overuse of antibiotics, it is important that the recommendations regarding the frequency of asymptomatic screening in MSM be reconsidered.” 

Other potential benefits of reducing the frequency of asymptomatic testing, according to the researchers, include reduction of healthcare utilisation and costs associated with asymptomatic screening, which could be redirected to other public health issues, including emerging sexually transmitted infections such as mpox. Importantly, new evidence suggests that a significant proportion of asymptomatic chlamydia and gonorrhoea infections of the throat and rectum spontaneously resolve and that low adherence to the current guidelines suggests that there are barriers to achieving the recommended frequency of screening. 

University of Melbourne’s Professor Deborah Williamson, Honorary Professor in the Department of Infectious Diseases at the Doherty Institute and co-author of the article, suggests that “whether the harms of frequent asymptomatic screening will outweigh benefits is unknown, but the ongoing threat of antimicrobial resistance is so great that action needs to be taken.” 

The researchers acknowledge that there are number of risks that would need to be mitigated before implementing changes to the recommended frequency of testing. These include ongoing three-monthly screening for HIV and syphilis in MSM, accessibility to effective HIV prevention measures such as PrEP, and that MSM who also have sex with women continue to engage in three-monthly screening given the significant reproductive and neonatal health impacts of gonorrhoea and chlamydia infection in women. Finally, they describe that engagement with affected communities would be essential to understand the acceptability and psychosocial impacts of the proposed changes and to identify what would be needed to allay concerns about less frequent screening.  

University of Melbourne’s Professor Jane Hocking, Epidemiologist and Implementation Researcher at the School of Population and Global Health and third co-author of the paper, says reducing frequency of screening for chlamydia and gonorrhoea should not, in any way, impact the current guidelines regarding other STIs such as HIV and syphilis.  

“Delayed diagnoses of syphilis, HIV and viral hepatitis have unacceptably high personal, maternal and public health consequences, and changes to the frequency of screening for these infections is not recommended.” 

To inform the acceptability and safety of this proposal Dr Williams says more research is required. “Qualitative research regarding the acceptability of current and proposed screening practices in different contexts and health settings, and quantitative assessment of the impacts of the change, including increased surveillance for clinical outbreaks and antimicrobial resistance will be key,” she says. 

In addition to the above being done to determine the suitability of this proposal, Dr Williams says modelling studies, educational campaigns for at-risk populations, clinical disease and resistance surveillance, and antimicrobial usage monitoring are critical further research areas prior to implementation of this proposed strategy.  

Peer review: The Lancet Infectious Diseases

 Funding: All three researchers are funded by various grants under the National Health and Medical Research Council (NHMRC).