Recent reports of episodes of Guillain-Barré syndrome, or GBS, following administration of quadrivalent human papillomavirus, or HPV4, vaccine have led the CDC to investigate whether a connection exists between the two events.
CDC Investigating Reports of GBS Tied to HPV Immunization
No Changes in Current Recommendations
By News Staff
9/26/2007
As of June 30, the Vaccine Adverse Event Reporting System, or VAERS, had received 13 reports of GBS associated with administration of HPV4 vaccine. That number, according to a "fast facts" document (2-page PDF; About PDFs) issued last month by the CDC, is consistent with what would be expected to occur by chance among individuals who hadd received a vaccine.
Although these 13 reports are currently undergoing expert review, according to the CDC document, initial findings indicate that
Although these 13 reports are currently undergoing expert review, according to the CDC document, initial findings indicate that
- six of the 13 reports occurred after the HPV4 vaccine, sold as Gardasil, was given alone;
- only two reports meet the case definition of GBS, occurred within six weeks after vaccination and occurred in patients who had received HPV4 vaccine alone;
- six of the 13 reports involved simultaneous receipt of both HPV4 vaccine and tetravalent meningococcal conjugate vaccine, or MCV4; and
- overall, the number of reports of GBS is consistent with what would be expected to occur by chance after a vaccination.
Reports of seven deaths among individuals who had received the HPV4 vaccine are being investigated, the document notes.
Vaccine Distribution, Reporting Background
Since Gardasil was licensed in June 2006, more than 7 million doses of the vaccine have been distributed throughout the United States, according to the CDC. However, given the lack of a national immunization registry, the number of people who have received the vaccine to date is not known.
Of a total of 2,531 reports associated with HPV4 administration that had been made to VAERS by the end of June of this year, nearly 95 percent were classified as nonserious (VAERS classifies serious adverse events as "involving hospitalization, death, disability, life-threatening illness or certain other medically important conditions.") Thus, the number of serious adverse events associated with this vaccine that have been reported to date is less then 6 percent of the total number of reports received.
By comparison, the overall average of VAERS reports that are classified as serious adverse events ranges from 10 percent to 15 percent.
Of a total of 2,531 reports associated with HPV4 administration that had been made to VAERS by the end of June of this year, nearly 95 percent were classified as nonserious (VAERS classifies serious adverse events as "involving hospitalization, death, disability, life-threatening illness or certain other medically important conditions.") Thus, the number of serious adverse events associated with this vaccine that have been reported to date is less then 6 percent of the total number of reports received.
By comparison, the overall average of VAERS reports that are classified as serious adverse events ranges from 10 percent to 15 percent.
Response to Consumer Group Analysis
The CDC's fast facts document was generated in response to statements made in an Aug. 15 press release from the National Vaccine Information Center, or NVIC, a nonprofit, consumer advocacy organization that describes itself as "dedicated to the prevention of vaccine injuries and deaths through public education and to defending the informed consent ethic."
According to the press release, an NVIC analysis (30-page PDF; About PDFs) "gives evidence for a reported association in VAERS between Gardasil and GBS, with a statistically significant increased risk of GBS and other serious adverse event reports when Gardasil is co-administered with other vaccines, especially meningococcal vaccine (Menactra)."
The CDC document notes that studies currently are being conducted to evaluate an already identified increased risk of GBS that may be associated with receipt of MCV4.
While acknowledging that investigation of adverse event reports associated with HPV4 administration continues, the CDC has made no changes to the current recommendations pertaining to HPV4 immunization at this time. As always, clinicians are encouraged to report adverse events associated with administration of HPV4 or any other vaccine, either online, by phone at (800) 822-7967, by toll-free fax at (877) 721-0366, or by e-mail.
According to the press release, an NVIC analysis (30-page PDF; About PDFs) "gives evidence for a reported association in VAERS between Gardasil and GBS, with a statistically significant increased risk of GBS and other serious adverse event reports when Gardasil is co-administered with other vaccines, especially meningococcal vaccine (Menactra)."
The CDC document notes that studies currently are being conducted to evaluate an already identified increased risk of GBS that may be associated with receipt of MCV4.
While acknowledging that investigation of adverse event reports associated with HPV4 administration continues, the CDC has made no changes to the current recommendations pertaining to HPV4 immunization at this time. As always, clinicians are encouraged to report adverse events associated with administration of HPV4 or any other vaccine, either online, by phone at (800) 822-7967, by toll-free fax at (877) 721-0366, or by e-mail.
