In England in 2015, among male SHC attendees, 84% (4,192/4,971) of syphilis diagnoses, 70% (22,408/32,095) of gonorrhoea diagnoses, 21% (12,805/60,514) of chlamydia diagnoses, 12% (1,502/12,208) of genital herpes diagnoses and 9% (3,539/38,214) of genital warts diagnoses were in MSM (figure 2a).The median (interquartile range) age of MSM diagnosed with these STIs ranged from 28 (23-36) years for genital warts to 36 (29-44) years for syphilis (figure 2b).
The number of diagnoses of STIs reported in MSM attending SHCs has risen sharply in recent years and accounts for the majority of the increased diagnoses seen among men (figure 1).
Gonorrhoea diagnoses increased by 21% (18,571 to 22,408), syphilis diagnoses by 19% (3,536 to 4,192), and chlamydia diagnoses by 8% (11,896 to 12,805) from 2014 to 2015 (figure 2c). This is consistent with recent trends as, by 2015, diagnoses of gonorrhoea (105%; 10,932 to 22,408), syphilis (95%; 2,147 to 4,192), chlamydia (52%; 8,416 to 12,805), genital herpes (21%; 1,246 to 1,502) and genital warts (12%; 3,149 to 3,539) had increased considerably since 2012
Gonorrhoea was the most commonly diagnosed STI among MSM in 2015: 10% (2,188/22,408) were infected at multiple anatomical sites. While 15% (3,400/22,408) were only infected in the pharynx, 25% (5,570/22,408) presented with rectal infections (figure 2d), suggesting significant numbers of transmissions occurred through condomless anal sex. High levels of gonorrhoea transmission are of particular concern, given the emergence of gonococcal resistance (including high-level resistance) to azithromycin, one of the antimicrobials used for treatment [5-7], and the first documented global case of treatment failure with first-line dual therapy reported recently in the UK .
From 2014 to 2015, diagnoses of lymphogranuloma venereum (LGV) increased by 39%, and a high proportion of patients diagnosed with LGV were co-infected with HIV (74%) and/or diagnosed with another STI or blood borne virus in the same year (63%) . There is also increasing concern about sexually transmissible enteric infections in MSM. For example, from 2014 to 2015, non-travel associated diagnoses of Shigella flexneri 2a in men increased by 30% while diagnoses in women remained low and stable, suggesting high levels of sexual transmission between MSM . Trends in LGV  and Shigella spp  are discussed further in accompanying articles in this issue of the HPR.
Several factors are likely to have contributed to the continued rise in diagnoses among MSM. Some of the increase in gonorrhoea and chlamydia diagnoses in MSM may be due to better detection through increased screening of extra-genital (rectal and pharyngeal) sites using NAATs , in response to current gonorrhoea testing guidance  and the LGV epidemic [15,16]. However, the impact of these developments will have progressively lessened in recent years as they have become more established. There is growing evidence that condomless sex associated with HIV seroadaptive behaviours, as has been reported in ongoing epidemics and outbreaks of
LGV, Shigella spp and syphilis, is leading to more STI transmission in this population [10,15]. There has been a steady increase in diagnoses of STIs in HIV-positive MSM since 2009, with a population rate of acute bacterial STIs up to four times that of MSM who were HIV-negative or of unknown HIV status. In 2015, 40% (1,653/4,141) of syphilis, 24% (2,948/12,503) of chlamydia and 20% (4,404/21,915) of gonorrhoea diagnoses in MSM were in HIV-positive men.
This suggests that rapid STI transmission is occurring in dense sexual networks of HIV-positive MSM . Furthermore, the number of new HIV diagnoses in MSM rose to 3,360 in 2014, consistent with the steadily increasing trend observed since 2010; this is thought to be due to high levels of ongoing HIV transmission and increased levels of HIV testing .
Men who have sex with men continue to experience high rates of STIs and remain a priority for targeted HIV and STI prevention and health promotion work. To address this need, HIV Prevention England (http://www.hivpreventionengland.org.uk/) have been contracted to deliver, on behalf of Public Health England, a range of activities that aim to reduce HIV incidence in MSM and other most at-risk populations. HIV Prevention England will provide system leadership, social marketing, amplification of local work and monitoring to promote among MSM and other most at-risk populations HIV testing, condom use, awareness of STIs and other evidencebased
HIV prevention interventions as well as addressing stigma and discrimination. Additionally, a targeted HPV vaccination pilot programme for MSM is being introduced in England this year to evaluate whether a national programme can be rolled out across the country at a later date. HPV vaccination of MSM could provide MSM with direct protection against HPV infection with the aim of reducing the incidence of genital warts and HPV-related cancers.