Trends and differences in sexual practices and sexually transmitted infections in men who have sex with men only (MSMO) and men who have sex with men and women (MSMW): a repeated cross-sectional study in Melbourne, Australia

Abstract

ObjectivesIn the 2010s, there has been an increase in sexually transmitted infections (STI) in men who have sex with men (MSM) in Australia, and since 2015 also in urban heterosexuals. Men who have sex with both men and women (MSMW) have characteristics that may differ from both men who have sex with men only (MSMO) and heterosexual men. We aimed to compare the sexual practices and the trends in HIV/STI positivity between MSMO and MSMW.DesignRepeated cross-sectional study.SettingA sexual health centre in Melbourne, Australia.ParticipantsMSM aged 18 years and above who attended the Melbourne Sexual Health Centre for the first time between 2011 and 2018. This includes 12 795 MSMO and 1979 MSMW.Primary outcome measuresDemographic characterics, sexual practices and HIV/STI positivity.ResultsCompared with MSMW, MSMO were more likely to practice anal sex and to have condomless receptive anal sex with casual male partners, and less likely to have a current regular relationship. Over the 8-year period, there was an increase in condomless receptive anal sex with casual male partners for both groups (MSMO: from 46.2% to 63.3%, ptrend <0.001; MSMW: from 41.3% to 57.9%, ptrend=0.011). Syphilis positivity increased in MSMO (from 5.5% to 7.9%, ptrend=0.012) and MSMW (from 0.9% to 6.4%, ptrend=0.004) and HIV remained stable. Gonorrhoea increased among MSMO from 2011 to 2014 (from 6.7% to 9.6%, ptrend=0.002), and remained stable from 2015 to 2018. MSMO had higher odds of testing positive for gonorrhoea (adjusted OR (aOR) 1.36, 95% CI 1.13 to 1.64), chlamydia (aOR 1.39, 95% CI 1.16 to 1.67), syphilis (aOR 1.74, 95% CI 1.37 to 2.22) and HIV (aOR 4.60, 95% CI 2.43 to 8.70) than MSMW.ConclusionsMSMW have overall lower condomless sex and lower HIV/STI positivity. In the last years, changes in sexual practices in MSM have affected both MSMW and MSMO leading to an increased STI risk.

Patterns of Sexual Practices, Sexually Transmitted Infections and Other Genital Infections in Women Who Have Sex with Women Only (WSWO), Women Who Have Sex with Men Only (WSMO) and Women Who Have Sex with Men and Women (WSMW): Findings from a Sexual Health Clinic in Melbourne, Australia, 2011–2019

“…However, these data must be interpreted with caution as the number of women who reported intravenous drug use was small in our study (n = 254). Similar patterns can also be observed in studies defining WSW according to sexual orientation (i.e., lesbian, bisexual, or heterosexual); a 2013 Australian populationbased study (Roxburgh et al, 2016) demonstrated more than a fourfold higher odds of intravenous drug use among lesbian and bisexual women in comparison to heterosexual women, and similar patterns can be observed when comparing gay and bisexual men to heterosexual men (Martin-Sanchez et al, 2020a, 2020b, 2020cPhillips et al, 2019). These findings may be due to stigmatization associated with sexual minority status and social norms in the LGBTQIA + community (Corliss et al, 2006).…”

“…Prior to this time, only women who were symptomatic or who were contacts of a known gonorrhea case were offered gonorrhea screening at MSHC, meaning that a large number of asymptomatic women may have been missed. This is supported by a 2020 studying highlighting that up to half of cases of gonorrhea in women are asymptomatic (Martin-Sanchez et al, 2020a, 2020b, 2020c. Finally, limitations may have arisen due to the low numbers of WSWO in comparison to WSMO.…”

Vaccine Candidates for the Control and Prevention of the Sexually Transmitted Disease Gonorrhea

“…In contrast to the increase in the notification rate of gonorrhea, there has been a decline in the HIV-1 notification rate from 4.5 to 4.0 per 100,000 population between 2013–2017 among MSM in Australia. Most of this reduction in HIV incidence can be attributed to the introduction of pre-exposure prophylaxis (PrEP) in 2016 [ 59 ].…”

Sexual mixing patterns among male–female partnerships in Melbourne, Australia

“…3 Recent Australian-based research found that there is no significant difference in urethral gonorrhoea positivity between men who have sex with men only and men who have sex with men and women, suggesting gonorrhoea transmission could subsequently be occurring between bisexual men and women. 4 Additionally, a study from a Melbourne centre found an increase in chlamydia positivity among lesbian women from no cases in 2011 to 2.7% in 2019 among those tested for STIs, 5 which raises questions regarding potential transmission of STIs from heterosexual populations by bisexual women to lesbian women, and whether sexual mixing has increased over a similar time period.…”

“…Additionally, these studies rarely examine whether bisexual men's partners are bisexual. 4 To the best of our knowledge, there have been very limited studies examining men and women having a partner who is bisexual. It is also unclear whether bisexual individuals are more likely to mix with other bisexual individuals than by random chance.…”