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Quick Links

bullet CDC HPV and HPV Disease Information
bullet CDC HPV Vaccine Information
bullet CDC Vaccine Safety Information
bullet HPV Questions and Answers
bullet FDA Center for Biologics Evaluation and Research
bullet To Report an Adverse Event in VAERS
bullet Related Information on Guillain-Barré Syndrome
bullet Information from FDA and CDC on Gardasil and its Safety

Summary of the Vaccine Adverse Event Reporting System (VAERS)

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. VAERS is unable to determine that a vaccine caused or did not cause an adverse event. Sometimes people who are vaccinated get sick from another cause unrelated to the vaccine.

Even though VAERS cannot determine that a vaccine caused an adverse event, it can give FDA and CDC important information that might signal a problem. If it looks as though a vaccine might be causing an adverse event, FDA and CDC will investigate further.

Facts about the Human Papillomavirus(HPV) Vaccine, Gardasil ®

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 16 million doses of Gardasil vaccine have been distrubuted in the United States. At this time, the U.S. does not have a national registry for immunization and vaccination, therefore cannot report the total number of people who have received Gardasil.

The FDA has licensed the vaccine as safe and effective. This vaccine has been tested in thousands of females (9 to 26 years of age) around the world. These studies have shown no serious side effects. The most common side effect is brief soreness at the injection site. CDC, working with the FDA and other immunization partners, will continue to monitor the safety of Gardasil.

VAERS Reports Related to Gardasil Vaccination June 8, 2006 through June 30, 2008

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

VAERS received 9,749 reports after Gardasil vaccination (6,667 were U.S. reports, 3,082 were foreign reports). Among the U.S. reports, more than 94% were reported as non-serious adverse events such as brief soreness at the injection site and headache. Less than 6% were reports of serious adverse events, about half of the average for vaccines overall.

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.


VAERS received 21 reports of death following Gardasil vaccination (17 were U.S. reports, 4 were foreign reports). Of the U.S. reports, only 12 reports contained the level of information adequate for further analysis. After careful review of those reports, VAERS could not establish a causal relationship between vaccination and death.

For the remaining 5 U.S. reports of death, one is in the process of being followed up, and for 4 reports, 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.

Guillan Barré Syndrome (GBS)

Note: GBS cases take longer to verify because each case must be confirmed manually by theClinical Immunization Safety Assessment Network (CISA) staff after reviewing the patient's medical records.

VAERS received 44 reports of Guillain-Barré Syndrome (GBS) after Gardasil vaccination (42 were U.S. reports, 2 were foreign reports). Of the 42 U.S. reports, 13 have been confirmed. Of the 13 confirmed U.S. GBS cases, 5 reported vaccination with Menactra and Gardasil at the same time.

Of the remaining 29 U.S. reports, 9 are pending additional follow-up, 8 did no meet the case definition for GBS (when evaluated by the CISA group), 11 are unconfirmed reports, and 1 case had symptoms of GBS that preceded vaccination.

Because GBS occurs at a rate of 1 to 2 per 100,000 people in their teens, 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.

To Submit a Report to VAERS

Reports of adverse events after getting a vaccine can be submitted to VAERS by phone at 1-800-822-7967, online at, or by mail to Vaccine Adverse Event Reporting System, P.O. Box 1100, Rockville, MD 20849.

Page last reviewed: August 28, 2008
Page last updated: August 28, 2008
Content source: Immunization Safety Office, Office of the Chief Science Officer


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