HPV Vaccine Safety and Effectiveness
HPV vaccines are very safe. Scientific research shows the benefits of HPV vaccination far outweigh the potential risks. Like all medical interventions, vaccines can have some side effects. More than 135 million doses of HPV vaccine have been distributed in the United States since the vaccine was introduced in 2006. The most common side effects associated with HPV vaccines are mild and include pain, redness, or swelling in the arm where the shot was given.
All vaccines used in the United States, including HPV vaccines, go through extensive safety testing before the U.S. Food and Drug Administration (FDA) licenses them. During clinical trials conducted before licensure:
- 9-valent HPV vaccine was studied in more than 15,000 males and females.
- Quadrivalent HPV vaccine was studied in more than 29,000 males and females.
- Bivalent HPV vaccine was studied in more than 30,000 females.
Each HPV vaccine was found to be safe and effective.
Fainting (syncope) can occur after any medical procedure, including vaccination. Syncope after any vaccination is more common in adolescents. Adolescents and adults should be seated or lying down during vaccination. Providers are encouraged to observe patients in seated or lying positions for 15 minutes after vaccination. This is to prevent any injuries that could occur from a fall during a syncopal event.
The HPV vaccine works extremely well. In the 10 years after the vaccine was recommended in 2006 in the United States, quadrivalent type HPV infections decreased by 86% in female teens aged 14 to 19 years and 71% in women in their early 20s. Research has also shown that fewer teens and young adults are getting genital warts and that cervical precancers are decreasing since HPV vaccines have been in use in the United States. Decreases in vaccine-type prevalence, genital warts, and cervical precancers have also been observed in other countries with HPV vaccination programs.
HPV vaccination prevents new HPV infections but does not treat existing HPV infections or diseases. HPV vaccine works best when given before any exposure to HPV. Most sexually active adults have already been exposed to HPV, although not necessarily all of the HPV types targeted by vaccination.
Cervical cancer screening is recommended for women beginning at age 21 years and continuing through age 65 years. Women who have received the HPV vaccine series should still be screened for cervical cancer beginning at age 21 years, in accordance with current cervical cancer screening guidelines.
Studies suggest that HPV vaccines offer long-lasting protection against HPV infection and therefore disease caused by HPV infection. Studies of the bivalent and quadrivalent vaccines have followed vaccinated individuals for more than 10 years and have found no evidence of protection decreasing over time. Duration of protection provided by HPV vaccination will continue to be studied.