Human Papillomavirus Vaccine Course Completion Among Gay and Bisexual Men Who Have Sex With Men From a Time-Limited HPV Vaccination Catch-Up Program in Victoria, Australia

Validation of self-reported human papillomavirus vaccination in young adult men who have sex with men

The Victorian Government introduced a time-limited human papillomavirus (HPV) catch-up program for gay, bisexual, and other men who have sex with men (GBMSM) aged ≤ 26 years in 2017-2019. We conducted a retrospective observational study to examine the accuracy of the self-report of HPV vaccination status using computer-assisted self-interviewing versus their immunization history via electronic health records. We included GBMSM aged 23-30 years visiting the Melbourne Sexual Health Centre (MSHC) in 2020-2021 because they were age-eligible for the HPV catch-up program in Victoria, Australia. Individuals who were unsure about their vaccination status were categorized as 'unvaccinated'. Of the 1,786 eligible men, 1,665 men self-reported their HPV vaccination status: 48.8% (n = 812) vaccinated, 17.4% (n = 289) unvaccinated, and 33.9% (n = 564) unsure. Self-reported HPV vaccination had a sensitivity of 61.3% (95%CI: 58.3 to 64.2%; 661/1079), a specificity of 74.2% (95%CI: 70.5 to 77.7%; 435/586), a positive predictive value of 81.4% (95%CI: 78.6 to 84.0%; 661/812), a negative predictive value of 51.0% (95%CI: 47.6 to 54.4%; 435/853), and an accuracy of 52.6% (95%CI: 50.1 to 55.0%). Our results showed that only half of GBMSM know and report their HPV vaccination status correctly. Novel approaches such as digital vaccine passports may be useful for individuals to accurately report their vaccination status to guide accurate clinical decisions and management.

Using an extended information-motivation-behavioral skills model to explain HPV vaccination intention among men who have sex with men only and men who have sex with men and women

Men who have sex with men and women (MSMW) have been reported to differ in psychosocial and sexual behavior patterns from men who have sex with men only (MSMO). However, results regarding the differences in HPV vaccination intention/behavior were inconclusive. We compared HPV vaccination intention between MSMO and MSMW and analyzed the differences in potentially associated factors in China. MSM participants were recruited online using a snowball sampling method. Cross-sectional data were collected via a questionnaire based on the extended information-motivation-behavioral skills model. Structural equation modeling was conducted to examine the relationship between the variables, followed by multi-group analysis to test differences between groups. Of 914 MSM, 77.68% were MSMO and 22.32% were MSMW. MSMW had a higher rate of reluctance to vaccinate than MSMO (23.53% vs. 16.20%, p = .016). Differences between the two groups were statistically significant in risky sexual behavior, behavioral skills, and promotional attitude. In both groups, promotional attitude was the most significant predictor of vaccination intention. Vaccination intention was directly influenced by motivation and indirectly by risky sexual behavior in MSMO, but not significantly in MSMW. Additionally, the direct effect of information on behavioral skills in MSMW was significantly greater than that in MSMO, but we did not find any effect of behavioral skills on vaccination intention. MSMW had lower vaccination intention than MSMO. MSMO may be influenced by risky sexual behavior and motivation, positively impacting their vaccination intention, unlike MSMW. Targeted strategies could help promote HPV vaccination, especially in MSMW.

Impact of including boys in the national school-based human papillomavirus vaccination programme in Singapore: A modelling-based cost-effectiveness analysis

Globally, gender-neutral Human Papillomavirus (HPV) vaccination programmes are gaining traction. Although cervical cancer remains the most prevalent, other HPV-related cancers are increasingly recognised as important, especially among men who have sex with men. We assessed if including adolescent boys in Singapore's school-based HPV vaccination programme is cost-effective from the healthcare perspective. We adapted a World Health Organization-supported model, Papillomavirus Rapid Interface for Modelling and Economics, and modelled the cost and quality-adjusted life years (QALY) associated with vaccinating 13-year-olds with the HPV vaccine. Cancer incidence and mortality rates were obtained from local sources and adjusted based on the expected direct and indirect vaccine protection for various population subgroups at an 80 % vaccine coverage. Moving to a gender-neutral vaccination programme with a bivalent or nonavalent vaccine could avert 30 (95 % uncertainty interval [UI]: 20-44) and 34 (95 % UI: 24-49) HPV-related cancers per birth cohort, respectively. At a 3 % discount rate, a gender-neutral vaccination programme is not cost-effective. However, with a 1.5 % discount rate, which puts more value on long-term health gains from vaccination, moving to a gender-neutral vaccination programme with the bivalent vaccine is likely cost-effective, with an incremental cost-effectiveness ratio of SGD$19 007 (95 % UI: 10 164-30 633) per QALY gained. The findings suggest the need to engage experts to examine, in detail, the cost-effectiveness of gender-neutral vaccination programmes in Singapore. Issues of drug licensing, feasibility, gender equity, global vaccine supplies, and the global trend towards disease elimination/eradication should also be considered. This model provides a simplified method for resource-strapped countries to gain a preliminary estimate of the cost-effectiveness of a gender-neutral HPV vaccination programme before investing resources for further research.

Human papillomavirus vaccine coverage in male-male partnerships attending a sexual health clinic in Melbourne, Australia

We aimed to investigate the sexual mixing by human papillomavirus (HPV) vaccination status in male-male partnerships and estimate the proportion of male-male partnerships protected against HPV. We analyzed male-male partnerships attending the Melbourne Sexual Health Center between 2018 and 2019. Data on self-reported HPV vaccination status were collected. Newman’s assortativity coefficient was used to examine the sexual mixing by HPV vaccination status. Assortativity refers to the tendency of individuals to have partners with similar characteristics (i.e. same vaccination status). Of 321 male-male partnerships where both men reported their HPV vaccination status, 52.6% (95% CI: 47.0–58.2%) partnerships had both men vaccinated, 32.1% (95% CI: 27.0–37.5%) partnerships had only one man vaccinated, and 15.3% (95% CI: 11.5–19.7%) had both men unvaccinated. The assortativity on HPV vaccination status was moderate (assortativity coefficient = 0.265, 95% CI: 0.196–0.335). There were about 15% of male-male partnerships where both men were not protected against HPV. Interventions targeting vaccinated individuals to encourage their unvaccinated partners to be vaccinated might increase the HPV vaccine coverage.

Human papillomavirus antibody levels following vaccination or natural infection among young men who have sex with men

BACKGROUND

Australia introduced a school-based gender-neutral human papillomavirus (HPV) vaccination program for schoolgirls and boys aged 12-13 years in 2013. We examined HPV type specific antibody levels in unvaccinated young men who have sex with men (MSM) with natural infection and compared these to levels in those vaccinated against HPV.

METHODS

Serum specimens at baseline were collected from MSM aged 16-20 years in the HYPER1 and HYPER2 studies, conducted between 2010-2013 and 2017-2019, respectively. Merck's 4-plex HPV competitive Luminex Immunoassay was used to quantify HPV6, 11, 16 and 18 specific antibodies. We compared antibody levels for each HPV genotype between unvaccinated men (HYPER1) and vaccinated men (HYPER2) using the Mann-Whitney U test.

RESULTS

There were 200 unvaccinated men and 127 vaccinated men included in the analysis. Median antibody levels among vaccinated men were significantly higher than levels among unvaccinated men for HPV6 (223 mMU/ml vs 48 mMU/ml, p<0.0001), HPV11 (163 mMU/ml vs 21 mMU/ml, p<0.0001), HPV16 (888 mMU/ml vs 72 mMU/ml, p<0.0001) and HPV18 (161 mMU/ml vs 20 mMU/ml, p<0.0001). The median time between antibody level measurement and last vaccine dose was 47.7 (IQR 40.4 to 54.1) months. Antibody levels did not change over time for up to 66 months for all four genotypes among vaccinated men.

CONCLUSION

Among young MSM vaccinated with the quadrivalent HPV vaccine, antibody levels for HPV 6, 11, 16 and 18 were significantly higher than those in unvaccinated MSM following natural infection. Antibody levels following vaccination appeared to remain stable over time.

Accuracy of Self-reported Human Papillomavirus Vaccination Status Among Gay and Bisexual Adolescent Males: Cross-sectional Study

BACKGROUND

Men who have sex with men are a risk group for anal human papillomavirus (HPV) and anal cancer. Australia introduced a universal school-based HPV vaccination program in 2013. Self-reported HPV vaccination status has been widely used in clinical and research settings, but its accuracy is understudied.

OBJECTIVE

We aimed to examine the accuracy of self-reported HPV vaccination status among gay and bisexual adolescent males.

METHODS

We included 192 gay and bisexual males aged 16-20 years from the Human Papillomavirus in Young People Epidemiological Research 2 (HYPER2) study in Melbourne, Australia. All participants had been eligible for the universal school-based HPV vaccination program implemented in 2013 and were asked to self-report their HPV vaccination status. Written informed consent was obtained to verify their HPV vaccination status using records at the National HPV Vaccination Program Register and the Australian Immunisation Register. We calculated the sensitivity, specificity, positive predictive value, and negative predictive value of self-reported HPV vaccination status.

RESULTS

The median age of the 192 males was 19 (IQR 18-20) years. There were 128 males (67%) who had HPV vaccination records documented on either registry. Self-reported HPV vaccination had a sensitivity of 47.7% (95% CI 38.8%-56.7%; 61/128), a specificity of 85.9% (95% CI 75.0%-93.4%; 55/64), a positive predictive value of 87.1% (95% CI 77.0%-93.9%; 61/70), and a negative predictive value of 45.1% (95% CI 36.1%-54.3%; 55/122).

CONCLUSIONS

Self-reported HPV vaccination status among Australian gay and bisexual adolescent males underestimates actual vaccination and may be inaccurate for clinical and research purposes.