What is Human Papillomavirus?

Expert Author
Dr. Douglas Raymond Hilbert Internist San Antonio, TX

Dr. Hilbert practices traditional internal medicine with evidence-based medicine and judicious use of medications when appropriate. Dr. Hilbert is a board-certified internal medicine physician as well as a Fellow of the American College of Physicians (FACP). This distinction is reserved for those recognized by their peers... more

What is HPV?

  • HPV is a small, double-stranded DNA virus
  • There are more than 200 types of HPV
  • HPV can infect either cutaneous or mucosal tissues

Natural History

  • Most HPV infections clear within 12 months
  • Carcinogenic HPV infections that last longer than 12 months increase the risk of both precancerous and cancerous lesions.
  • In the US, in women, most precancerous lesions occur 10 years after becoming sexually active.

Anogenital Warts

  • Over 40 HPV strains can infect the genital tract
  • Sites of infection include: cervix, vulva, vaginal introitus, penis, scrotum, perineum, anal canal, perianal region

15 Subtypes of HPV are Associated with Cancer

  • HPV 16 is most likely to progress to cancer

HPV-Related Oropharyngeal Cancers

  • HPV-related oropharyngeal cancers in men are now more common than HPV related cervical cancer in women
  • Cancers can be in the base of the tongue, oropharynx, tonsil, and larynx

Non-HPV Related Oropharyngeal Cancers

  • Alcohol and smoking are the greatest risk factors
  • HPV now causes more head and neck cancers than alcohol and smoking
  • Cancers can be in the base of the tongue, oropharynx, tonsil, and larynx 

Not all Vulvar and Vaginal Cancer is HPV Related

  • Thus, still important to have regular gynecological examinations

HPV Vaccination

  • The Gardasil-9 Vaccine is used in the US
  • Gardasil-9 protects against 9 different strains of HPV
  • Even though there are many more, immunity to these 9 protect against most strains
  • Most importantly, it covers the ones known to cause cancers and genital warts.
  • The vaccines are extremely effective, and for many populations, dramatically reduce the risks of many cancers
  • It is best to start vaccine series prior to the onset of sexual activity. Thus, we start the 3 shot vaccination series at age 9.
  • Even though 15 or more strains of HPV cause cancer, there is what is called cross-reactivity for many HPV strains. Thus, the Gardasil 9 vaccine directly provides immunity for the most common strains, which happens to provide immunity to the other strains given how closely they are related genetically. 
  • CDC updated guidelines now recommend that all persons 45 and under get vaccinated.

 

HPV is very prevalent and many studies suggest upwards of 80% of women have been infected by at least one strain by age 50. Rates for men are similar. Early detection and monitoring are very important. Currently, the only site tested for HPV is the cervix, other sites are tested as part of research protocols. With any disease, the best approach is prevention, and luckily now prevention is greatly enhanced by vaccination.