Gardasil Vaccine Adverse Event Reporting To CDC

Armen Hareyan's picture

On June 8, 2006, the FDA licensed Gardasil, the first vaccine developed to prevent cervical cancer caused by certain kinds of human papillomavirus (HPV). Since then, more than 12 million doses of Gardasil vaccine have been distributed. However, CDC also received 7,802 reports on side effects of Gardasil.

The Vaccine Adverse Event Reporting System (VAERS) is a national program of CDC and the Food and Drug Administration (FDA) that monitors the safety of vaccines after they are licensed. VAERS receives reports of adverse events that occur after people receive vaccines. These reports provide valuable information that helps CDC and FDA make sure vaccines are safe, and that the benefits of vaccination outweigh the risks.

Anyone can report a health problem in VAERS. Just because a health problem is reported to VAERS does not mean it was caused by a vaccine. Usually, only scientific research can determine if a vaccine caused a health problem, or if it was just a coincidence.

Gardasil Human Papillomavirus (HPV) Vaccine

On June 8, 2006, the FDA licensed Gardasil®, the first vaccine developed to prevent cervical cancer caused by certain kinds of human papillomavirus (HPV). Since then, more than 12 million doses of Gardasil vaccine have been distributed. In 2006, a total of 2,151,000 doses were distributed and in 2007, another 11,317,902. At this time, the U.S. does not have a national registry for immunization and vaccination and therefore cannot report the total number of people who have received Gardasil.

Gardasil has been tested in more than 11,000 females 9 to 26 years of age in many countries around the world, including the United States. These studies found the HPV vaccine is safe and causes no serious side effects. The most common side effect is injection site pain.

VAERS Reports Related to Gardasil Vaccination
June 8, 2006 through April 30, 2008
Note: VAERS defines serious adverse events by the Code of Federal Regulations as adverse events involving hospitalization, death, permanent disability, and life-threatening illness. Also, VAERS data are updated continuously and the number of reports will vary depending on the date of analysis.


The following reports were submitted to VAERS between the date the vaccine was licensed (June 8, 2006) and April 30, 2008.

VAERS received 7,802 reports after Gardasil vaccination in the U.S. Less than 7% reported serious side effects, about half of the average for vaccines overall.


VAERS received 15 reports of death following Gardasil vaccination in the U.S. Only 10 reports contained the level of information adequate for further analysis. After careful review of those reports we could not establish the causal relationship between vaccination and death. For the remaining 5 reports of death, we were unable to obtain any patient identifying information; therefore we could not confirm death outcomes. Note: While Gardasil was being tested in the U.S. before it was licensed, 10 people in the group that received the HPV vaccine and 7 people in the placebo group died during the trials. None of the deaths was considered vaccine-related.

Guillain-Barré Syndrome (GBS)

Note: GBS cases take longer to verify because each case must be confirmed manually by CISA staff after reviewing the patient's medical record.

VAERS received 31 reports of Guillain-Barré Syndrome (GBS) after Gardasil vaccination in the U.S. Ten have been confirmed. Of the 10 confirmed GBS cases, 5 reported vaccination with Menactra and Gardasil at the same time. Of the remaining 21 reports, 7 did not meet the case definition for GBS (when evaluated by the Clinical Immunization Safety Assessment (CISA) group), 1 had symptoms of GBS prior to vaccination, 4 are unconfirmed reports, and 9 are pending additional follow-up.

Because GBS occurs at a rate of 1 to 2 per 100,000 person-years during the second decade of life, it is likely that some cases occur after vaccination by chance alone and are not caused by vaccination. Among 9 to 26 year-olds, the number of reports of GBS received by VAERS are within the range that could be expected to occur by chance alone after a vaccination. Studies are underway to evaluate the risk of GBS that may be associated with receipt of Menactra vaccine.

Page last reviewed: June 16, 2008
Page last updated: June 16, 2008
Content source: Immunization Safety Office, Office of the Chief Science Officer