Potential impact of a nonavalent anti HPV vaccine in Italian men with and without clinical manifestations

Human papilloma virus infection (HPV) is the most common sexually transmitted disease. Little is known about male infection. Nonavalent vaccine against types 6/11/16/18/31/33/45/52/58 was approved and neutral gender immunization programs have been proposed. This study evaluates the potential impact of nonavalent vaccine compared to quadrivalent in male living in Sicily (Italy). 58.7% of samples were HPV positive and forty-four types of HPV were identified. A significant higher estimated coverage of nonavalent vaccine than quadrivalent was observed (64.3% vs. 45.8%), with absolute and relative additional impact of 20.1% and 47.2%, respectively. Low impact of the vaccine were calculated as the empirical probability of HPV genotypes 6/11/16/18/31/33/45/52/58 alone or in combination; the high impact as empirical probability of HPV6/11/16/18/31/33/45/52/58 genotypes alone or in association with other genotypes. The potential impact of the nonavalent vaccine vs quadrivalent was significant for low and high impact (29.7% > 18:8%; 34:6% > 26.6%, respectively). Particularly, in men with lesions and risky sexual contact was significant only for low impact (35.5% > 29.7%; 31.4% > 19.7%, respectively). In partners with positive females was significant for low impact (26.3% > 15.1%) and high impact (33.7% > 23.2%). Nonavalent vaccine offers broader protection in men with HPV positive partners, who would have a potential role in the transmission of the infection.