Bisexual men are “disproportionately affected” by sexually transmitted infections, according to new research.

The Centre for Disease Control and Prevention study, published today in the American Journal of Preventive Medicine, found that bisexual men were left vulnerable to diseases because their public health needs were often unmet.

The study found that although only 2% of the sexually active population report having sex with both men and women (MSMW), a raft of factors leave them more vulnerable to infections than men who exclusively have sex with men or women.

According to the study, 21% of MSMW report treatment for STIs in the past year, compared to 12% for gay men, and 2.3% for straight men.

They were also less likely to be screened for HIV than men who exclusively have sex with men, which could lead to undiagnosed HIV and unknowing transmission.

Researcher Dr. William Jeffries wrote: “Biphobia can manifest in erroneous beliefs that MSMW are gay men who have not disclosed their sexual orientation and, particularly for black men, responsible for HIV transmission to women.

“Experiencing these sentiments can contribute to MSMW’s social isolation and psychological distress, which in turn may promote HIV/STI risk through substance use, sexual risk behaviors, and the avoidance of prevention services.”

“MSMW’s increased likelihood of insertive sex without a condom, as well as commonly occurring oral sex with men and women, likely increase MSMW’s vulnerability to STIs readily acquired via penile-insertive and oral sex.

“Moreover, receptive and insertive sex without a condom with men (no matter how common) makes MSMW more vulnerable to HIV than men who only have sex with women because HIV is more prevalent among men than women in the United States.”

Jeffries suggests that sexual health programmes should do more to target bisexual men, instead of heteronormative and gay-exclusive campaigns.

He concludes: “Sexual health promotion for MSMW should not be limited to HIV/STI prevention alone.

“Recognition of MSMW’s unique sexual and social experiences can lay the foundation necessary for ensuring that these men have healthy and fulfilling sexual experiences.

“Purposefully designed and tailored efforts for MSMW are indispensable for improving the sexual health of this vulnerable population.”