HPV Vaccine Safety and Effectiveness Data
More than 12 years of monitoring and research have accumulated reassuring evidence that human papillomavirus (HPV) vaccination provides safe, effective, and long-lasting protection against cancers caused by HPV infections.
Data from Clinical Trials
Each HPV vaccine—9-valent HPV vaccine (Gardasil® 9), quadrivalent HPV vaccine (Gardasil®), and bivalent HPV vaccine (Cervarix®)—went through years of extensive safety testing before it was licensed by the U.S. Food and Drug Administration (FDA). FDA only licenses a vaccine if it is safe and effective, including that the benefits outweigh the risks. Each vaccine was found to be safe and effective in clinical trials.
Gardasil® 9 was studied in clinical trials with more than 15,000 females and males.
Gardasil® was studied in clinical trials with more than 29,000 females and males.
Cervarix® was studied in clinical trials with more than 30,000 females.
Vaccine Safety Monitoring Data
With more than 120 million doses of HPV vaccines distributed in the United States, there are robust data showing that HPV vaccines are safe.
- Like any vaccine or medicine, HPV vaccines can cause side effects. The most common side effects reported through CDC’s Vaccine Adverse Event Reporting System (VAERS) are pain, redness, or swelling in the arm where the vaccine was given, dizziness, syncope (fainting), nausea, and headache.
- With the exception of syncope, which is more common among adolescents after receiving any vaccine, there have been no confirmed adverse events occurring at higher than expected rates following HPV vaccination.
- On very rare occasions, a person may have a serious allergic reaction (anaphylaxis) to any vaccine, including HPV vaccines. In the United States, anaphylaxis following vaccination has a reported rate of 3 cases per 1 million doses administered. People with severe allergies to any component of a vaccine should not receive that vaccine.
The United States monitors safety of all vaccines through several systems:
- Vaccine Adverse Events Reporting System (VAERS) is a spontaneous reporting system that serves as an early warning system to detect possible safety problems that may be related to vaccination. Anyone can submit a report to VAERS. However, it is generally not possible to find out from VAERS data if a vaccine caused the adverse event, and the reports often lack details and sometimes contain errors.
- Vaccine Safety Datalink (VSD) is a collaborative project between CDC and eight healthcare organizations, which monitors the safety of vaccines and conducts rigorous vaccine safety assessments.
- Clinical Immunization Safety Assessment Project (CISA) addresses vaccine safety clinical research and assesses complex clinical adverse events following vaccination.
- Post-licensure Rapid Immunization Safety Monitoring System (PRISM)external icon, a part of FDA’s Sentinel Systemexternal icon, is used to evaluate the safety of vaccines from health insurance claims data.
While only Gardasil® 9 has been available for use in the United States since late 2016, safety studies of Gardasil® have provided important safety information relevant for Gardasil® 9 (Gardasil® and Gardasil® 9 are similar types of vaccines and are produced by the same manufacturer). Studies of Cervarix® have also shown a favorable safety profile. While the vaccines target some different HPV types, all three HPV vaccines are similar and made from a single protein of the human papillomavirus.
What is an adverse event?
- An “adverse event” is any health problem that happens after a shot or other vaccine. An adverse event might be truly caused by a vaccine, or it might be pure coincidence.
- An adverse event is defined by law as “serious”external icon if it is life-threatening or results in death, a persistent or significant disability or incapacity, congenital anomaly or birth defect, hospitalization, or prolongation of existing hospitalization.
- VAERS data alone usually cannot be used to answer the question, “Does a certain vaccine cause a certain adverse event?” This is mainly because adverse events reported to VAERS may or may not be caused by vaccines.
- VAERS reports help provide medical professionals at CDC and FDA with a signal of a potential adverse event that needs to be studied further.
Data on Gardasil® 9 (9vHPV)
Data on Gardasil® (4vHPV)
Gardasil® is no longer available in the United States.
Data on Cervarix®(2vHPV)
Cervarix® is no longer available in the United States and was not administered at any of the VSD sites; therefore, no safety monitoring was conducted through the VSD network.
Vaccine Safety Studies of Specific Conditions
Complex Regional Pain Syndrome (CRPS)
Postural Orthostatic Tachycardia Syndrome (POTS)
Primary Ovarian Insufficiency (POI)
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)
Autoimmune Conditions
Several large studies have looked at whether HPV vaccines cause autoimmune disease. Many different autoimmune diseases have been studied, including Guillain–Barré syndrome, multiple sclerosis, and diabetes. To date, these studies have not found any association between HPV vaccination and autoimmune conditions.(6-9, 12-18, 20, 26)
Death
Vaccine Effectiveness Studies
Studies in the United States and other countries have shown that HPV vaccination is preventing cancer-causing infections, genital warts, and cervical precancers. This suggests that there will be decreases in cancers caused by HPV in the future.
Duration of Protection Studies
Data from clinical trials and ongoing research show that HPV vaccination provides long-lasting protection.
- Protection by HPV vaccination lasts at least 10 years without becoming less effective.(33, 34)
- Studies are ongoing to further evaluate the duration of protection.
- No data indicate that the protection from HPV vaccination lessens over time.