A study led by researchers from Monash University - Australia and Alfred Health -Australia that also included experts from the University of Melbourne has found a 70 per cent reduction in one type of human papillomavirus (HPV) in gay and bisexual men after the implementation of the school-based HPV vaccination program.
Even Leading Korean Actors Are Promoting That Both Straight And Gay Youths Get HPV Vaccines To Prevent HPV Associated Cancers.
Typically, anal infection with high-risk human papillomavirus (HPV) genotypes 16 and 18 and anal cancer are overrepresented in men who have sex with men (MSM).
The study investigated HPV prevalence in young MSM before and after the implementation of a school-based quadrivalent HPV (genotypes 6, 11, 16, and 18) vaccination program for boys in Australia in 2013.
The repeated cross-sectional study involved MSM aged 16–20 years who were recruited from two successive birth cohorts via sexual health clinics and the community in Melbourne, Australia.
The initial cohort was before the implementation of gender-neutral vaccination (HYPER1 study, done in 2010–12, NCT01422356), and the second was the post-vaccination cohort (HYPER2 study, done in 2017–18, NCT03000933).
Males who self-identified as being same-sex attracted were enrolled, and those recruited via the HYPER2 study had to be resident in Australia since 2013 to ensure eligibility. Study procedures were done in the Melbourne Sexual Health Centre. A clinician-collected anal swab and self-collected penile swab and oral rinse were tested for 28 HPV genotypes, and data on demographics and sexual health practices were collected via questionnaires. Only assessable samples were included in the analyses.
The study team compared anatomical site-specific prevalence of HPV genotypes between cohorts by calculating the prevalence ratio, adjusting for age, circumcision, and sex with women. Herd protection was also assessed, by calculating the adjusted prevalence ratios by vaccination status.
A total of 400 MSM, 200 per cohort, were included in the study. In both cohorts, the median number of lifetime male partners was ten (IQR 5–25).
The study findings showed that the prevalence of any anal quadrivalent vaccine-preventable HPV genotype was higher in the pre-vaccination cohort (54 [28%] of 193) than in the post-vaccination cohort (14 [7%] of 193; adjusted prevalence ratio [PR] 0·24, 95% CI 0·14–0·42), largely driven by decreases in HPV6, followed by HPV11, 16, and 18.
There was also a significant reduction in anal HPV16 and 18 in the post-vaccination cohort from the pre-vaccination cohort (0·31, 0·14–0·68). The prevalence of any penile quadrivalent vaccine-preventable HPV genotype was also higher in the pre-vaccination cohort (21 [12%] of 177) than in the post-vaccination cohort (11 [6%] of 179; 0·48, 0·24–0·97), driven by decreases in HPV 6 and 11, but not by 16 and 18. The prevalence of any oral quadrivalent vaccine-preventable HPV genotype was higher in the pre-vaccination cohort (seven [4%] of 200) than in the post-vaccination cohort (one [1%] of 199; 0·10, 0·01–0·97); there were no cases of oral HPV6 or 11 detected in HYPER2.
Comparing the pre-vaccinated cohort with the 149 confirmed vaccinated men from HYPER2 showed a reduction in any quadrivalent vaccine-preventable HPV genotype for anal (0·09, 0·03–0·25) and penile (0·18, 0·05–0·59) infection but not for oral infection (0·17, 0·03–1·08).
The study findings showed that a reduction in anal, penile, and oral quadrivalent vaccine-targeted genotypes occurred in young MSM following the implementation of a school-based gender-neutral HPV vaccination programme. The fall in anal HPV16 and 18 may lead to a reduction in the incidence of anal cancer.
The study findings were published in the peer reviewed journal: The Lancet Infectious Diseases. https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(20)30687-3/fulltext
Most importantly the study findings provided evidence that it is important for all gay men and gay youths to receive HPV vaccines at an early age as possible to prevent the development of various HPV related cancers later in their lives.
The HYPER2 study led by Associate Professor Dr Eric Chow, found there was a significant reduction in all four vaccine-preventable genotypes in gay/bisexual men aged 16-20 years following the introduction of the vaccine for boys in 2013.
To date, Australia is one of the first and few countries that have both boys and girls vaccination programs for HPV. The vaccine covers four genotypes: 6/11/16/18. Genotypes 6/11 cause about 90 per cent of the genital wart cases and genotypes 16/18 cause about 70 per cent of cervical and anal cancers.
It was also noted that this is the first study to show that the implementation of the gender-neutral program can reduce high-risk anal HPV and potentially reduce the incidence of anal cancer in gay and bisexual men.
The repeated cross-sectional study recruited 400 gay and bisexual men with a median age of 19 years from sexual health clinics and the community in Melbourne.
The study findings were compared with the HYPER1 group of 200 gay/bisexual men pre-vaccination in 2010-2012 and the HYPER2 group of 200 gay/bisexual men post-vaccination in 2017-2018.
Importantly the findings showed a reduction in anal quadrivalent genotypes from 28 per cent down to 7.3 per cent and penile quadrivalent genotypes also lower in the post-vaccination group 6.1 per cent compared to 11.9 per cent.
The incidence of anal cancer incidence has increased globally among men over the last three decades. It is overrepresented among gay and bisexual men, particularly those living with HIV.
A detailed meta-analysis estimated the incidence of anal cancer to be 45.9 per 100,000 among HIV-positive MSM.
Findings from the HYPER2 study suggest that male vaccination may lead to a potential reduction in anal cancer among gay and bisexual men in Australia, which is similar to the reduction in cervical cancer among Australian women after the HPV vaccination program launched in 2007.
Dr Chow told Gay Health News, "The vaccine is effective in reducing HPV-related diseases and showing some promising evidence that this may lead to a reduction in HPV-related cancer in the future."
The study team strongly advocated that all boys should also take the vaccines at an early age and youths who have identified themselves as gays should also ensure that they receive the HPV vaccines.
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