Incidence of and risk factors for type-specific anal human papillomavirus infection among HIV-positive MSM

An anal cancer screening program for MSM in Italy: Prevalence of multiple HPV types and vaccine-targeted infections

BACKGROUND

Elevated HPV infection rates have been described in HIV-positive males, placing these subjects at high risk of anal neoplasia. Bivalent, quadrivalent, and nonavalent vaccines to prevent HPV infection have been developed, and recently proposed for gender-neutral immunization programs.

OBJECTIVES

In order to estimate the benefit that could be obtained by vaccination of HIV-positive men who have sex with men (MSM), we aimed at describing the frequency of multiple and vaccine-targeted HPV infections in MSM enrolled in an anal cancer screening program.

STUDY DESIGN

The anal cancer screening program was conducted between July 2009 and October 2012. Mucosal anal samples were tested for HPV DNA using MY09/MY11 PCR primers and, if positive, genotyped using the CLART2HPV Clinical Array (35HPV types).

RESULTS

A total of 220 MSM were screened and 88.6% were positive for HPV DNA: in 86.5% at least one high-risk (HR) type was found and in 13% only low-risk (LR) HPV were found. Multiple infections accounted for 84.5% of HPV DNA-positive cases and overall 160 different HPV genotype combinations were recognized (only three combinations were detected in more than one patient each). Based on strain coverage, at least one vaccine-targeted HPV type was found in 38.9%, 64%, and 78.4% of cases when considering bivalent, quadrivalent and nonavalent vaccines, respectively. At least one HR vaccine-targeted strain was found in 39% of MSM for bivalent and quadrivalent vaccines, and in 64% of cases for nonavalent prevention.

CONCLUSIONS

Anal HPV infections in unvaccinated mostly HIV-infected MSM are highly prevalent. The majority of this population has multiple infections with an extremely heterogeneous number of genotype combinations. The nonavalent vaccine could theoretically have prevented a minimum of one HR HPV type in two thirds of subjects.

Human Papillomavirus (HPV) Infections and the Importance of HPV Vaccination

HPV persistence is necessary for the development of anogenital cancer. Studies show that cervical and anal HPV infections in women and in men who have sex with men are common. Clearance of HPV infection is similarly common; few individuals show persistence unless they are HIV-infected. HIV strongly influences the development of cervical and anal cancer, as well as their pre-malignant counterparts. Women with cervical and vulvar HPV-associated lesions have higher rates of anal cancer than the general population. HPV also plays an important role in pathogenesis of head and neck cancers, particularly oropharyngeal cancer. Two commercially available HPV vaccines have been proven to be safe and efficacious against cervical HPV16/18 infections and associated precancerous lesions; one of these has also been shown to prevent HPV16/18-associated anal lesions. The FDA has also just approved a new nonavalent HPV vaccine. HPV vaccines will play an important role in prevention of HPV-associated cancers.

Safety and immunogenicity of a quadrivalent human papillomavirus vaccine in HIV-infected and HIV-negative adolescents and young adults

Human papillomavirus (HPV) infection is highly prevalent and can lead to cancer; the development of safe and efficacious vaccines for HPV is a major public health concern. The two licensed HPV vaccines contain recombinant virus-like particles of HPV 16 and 18; one of such vaccines also protects against HPV types 6 and 11 which cause genital warts. We determined safety and immunogenicity of quadrivalent HPV vaccine in HIV-infected and HIV-negative adolescents and young adults, aged 13-27 years. The seroconversion rate, assessed by antibody titers, 1 month after the administration of the third vaccine dose was 0.85 (95% CI 0.75-0.95) in the HIV-infected group and 0.91 (0.83-0.99) in the HIV-negative subjects (p=0.52). The vaccine was generally safe and well tolerated; the most common side effect was local pain and the most frequent systemic side effect was headache. This is the first report on response to HPV vaccination in both female and male HIV-infected adolescents and young adults and highlights that this population may benefit from HPV immunoprophylaxis. Further studies are needed to examine the long term efficacy of this vaccine in HIV-infected individuals.