Viral Hepatitis and Human Papillomavirus Vaccination during HIV Pre-Exposure Prophylaxis: Factors Associated with Missed Vaccination

Background:We evaluated factors associated with lack of triple vaccination (hepatitis A virus [HAV], hepatitis B virus [HBV], and human papillomavirus [HPV]) among men who have sex with men using pre-exposure prophylaxis (PrEP).Setting:PrEP users at the San Raffaele Scientific Institute, Italy, with ≥1 follow-up visit (May 2017-2022).Methods:Participants were considered protected if (1) before PrEP access: positive serology (IgG-HAV+, hepatitis B surface antigen >10 mUI/mL) or vaccination history was recorded and (2) after starting PrEP: ≥1 dose of each vaccination was administered. Individuals were considered fully protected if they received the following before/during PrEP access: HAV vaccination/infection, HBV vaccination/infection, and HPV vaccination. χ2and Kruskal-Wallis tests were used to compare characteristics of those fully, partially, and not protected. Factors associated with the lack of triple vaccination were assessed by using multivariable logistic regression and classification tree analysis.Results:Overall, 473 men who have sex with men were considered: 146 (31%) were fully protected, 231 (48%) partially, and 96 (20%) were not. Daily-based PrEP users (fully: 93, 63.7%; partially: 107, 46.3%; and not protected: 40, 41.7%; P = 0.001) and those with a sexually transmitted infection at the first visit (43, 29.5%; 55, 23.8%; 15, 15.6%; P = 0.048) were more frequently fully protected. At multivariable analysis, the odds of lack of triple vaccination was lower among daily-based users (adjusted odds ratio = 0.47, 95% confidence interval = 0.31-0.70, P < 0.001). Classification tree analysis showed that among daily-based users, with sexually transmitted infection prior and at the first PrEP visit, there was a lower chance of lack of triple vaccination (P = 44%).Conclusions:Strategies targeting PrEP users at risk of missing HAV, HBV, and HPV vaccinations need to be implemented, focusing mostly on event-based users.