By: Quyen Nguyen, MD
Two common questions from patients are, “What is HPV, and who should get the HPV vaccine?” The Human papillomavirus (HPV) is a common sexually transmitted disease that affects approximately 25 percent of the U.S. population, and more than 100 types of HPV have been identified. HPV is transmitted during intimate sexual contact, which includes vaginal and anal intercourse. Condoms lower the chance of infection, but do not fully protect against HPV.
HPV and cancer
Many people never know that they have been infected and may pass HPV on to their partners without ever knowing it. This makes HPV difficult to manage—the majority of patients are asymptomatic, and infections can resolve on their own. Problems arise when HPV persists, which can happen for years before detection. Continued HPV infections can cause cancers of the cervix, vagina, vulva, anus, penis and oropharynx. Different HPV types have been labeled as high risk or low risk for causing cervical cancer. HPV types 6 and 11 are low risk and cause the majority of genital warts. HPV types 16 and 18 are higher risk, accounting for 70 percent of cervical cancers. A smaller percentage is caused by other high-risk HPV types, such as 31, 33, 45, 52 and 58.
To prevent HPV-related diseases, three types of HPV vaccinations are currently available.
- Gardasil – targets HPV types 6, 11, 16 and 18
- Cervarix – targets HPV types 16 and 18
- Gardasil 9 – targets HPV types 6, 11, 16, 18, 31, 33, 45, 52 and 58
Gardasil 9 provides the greatest coverage and is the only HPV vaccine currently available in the U.S. It is injected into the muscle of the upper arm or thigh.
HPV vaccination can be given as early at 9 years of age, but is generally recommended at 11 to 12 years. The current Centers for Disease Control and Prevention (CDC) recommendation is to vaccinate up to the age of 26 in females and 21 in males. After the age of 26, there is limited or minimal protection against HPV-related diseases with vaccination. Children who are 14 years and younger will need only two shots total, spaced six to 12 months apart. If the time between the two doses is 5 months or less, a third dose will be required. Children older than 14 will need three shots, with subsequent doses at two and six months after the initial vaccination. If the recipient’s immune system is compromised, all three doses are recommended. Interrupted and missed doses can be resumed without restarting the series.
HPV vaccination safety
The U.S. Food and Drug Administration (FDA) has extensively tested the HPV vaccine to ensure patient safety. Side effects from the HPV vaccine aren’t serious and may include pain or redness at the injection site, dizziness, fainting, nausea and headache.
Data on the vaccine’s efficacy is available for about 10 years following vaccination. Surveillance studies have demonstrated vaccine safety and efficacy with excellent antibody responses, suggesting long-lasting protected immunity. The greatest protection is achieved if the vaccine is given before becoming sexually active. However, patients with prior documented HPV infection—such as a history of genital warts or positive HPV on Pap smear—can still benefit from the vaccine, as it can provide protection from other HPV types that have not been acquired. HPV immunization does not protect 100 percent against all HPV types known to cause cervical cancer, and it is not used as treatment for clearing HPV infections acquired prior to immunization. Cervical cancer screening is still indicated after vaccination.
HPV infections can have lasting health effects. Every year, numerous men and women are diagnosed with pre-cancers and cancers caused by HPV. The HPV vaccination can help decrease these numbers and aid in disease prevention.