Section of Pediatric Infectious Diseases, The University of Chicago, Chicago, Illinois.
The human papillomavirus (HPV) causes more than 99% of all cervical cancers (see Am J Med Resource Center: http://supplements.amjmed.com/2011/HPV/). Exposure to HPV infections occurs in a high proportion of the overall population; however, 2 safe and effective vaccines, HPV2 and HPV4, are approved for the prevention of HPV-16 and HPV-18 infection, the most common causes of cervical cancer. Additionally, HPV4 prevents HPV-6 and HPV-11-related genital warts. While prevention of cervical cancer in women has been the initial aim of vaccination programs, it has now become apparent that HPV causes other types of cancer as well, including vulvar and vaginal cancers in women, penile cancer in men, and anal cancer in both sexes. Furthermore, these viruses have been implicated in head and neck cancers in both men and women as well. It is estimated that HPV-related cancers occur in 10,000 American males annually, suggesting that limiting vaccination programs to females may be underserving a significant proportion of the population. The efficacy of the 2 available vaccines against oncogenic HPV is more than 90% for both cervical and anal intraepithelial neoplasia. For those receiving the HPV4 vaccine, efficacy against genital warts is nearly 90%. Adverse effects are few and include episodes of syncope in the period immediately following vaccination. Benefits of vaccinating males include reduction in disease burden in men and enhanced herd immunity to reduce disease burden in women.