April 30, 2009 (Seattle) -- Girls and women who receive the Gardasil vaccine to prevent cervical cancer may be at
increased risk of a rare but serious disorder of the nervous system in the
first few weeks after getting their shots, researchers report.
Overall, the vaccine does not raise the odds of developing Guillain-Barre
syndrome (GBS), a disorder of the peripheral nervous system, says Nizar
Souayah, MD, of the University of Medicine and Dentistry of New Jersey in
“But there is clear evidence from our database of an increased incidence of
Guillain-Barre syndrome in the first six weeks, especially the first two weeks,
after vaccination,” he tells WebMD.
Still, the risk is extremely low: 26 in 10 million in the first two weeks
and 30 in 10 million in the first six weeks after vaccination. That compares to
5 in 10 million odds in the general population, Souayah says.
In response to the study, a spokesperson for Merck, which makes Gardasil,
notes that the CDC says that “the data do not currently suggest an association
between Gardasil and GBS.”
The findings were presented at the annual meeting of the American Academy of
Guillain-Barre syndrome is a rare nervous system disorder in which the
body's immune system attacks part of the nervous system. This immune system
malfunction is usually triggered by an infection, such as with flu virus, or other illness.
Occasionally, surgery or vaccinations will trigger the syndrome.
The link between Guillain-Barre syndrome and vaccinations isn't clear. But
researchers say concerns emerged after an association was noticed during the
1976-1977 "swine flu" season. Since then,
“there is always a concern when any vaccine program is introduced,” says Ken
Gorson, MD, a neurologist at Tufts University/St. Elizabeth’s Medical Center in
January 2007, the CDC added Gardasil to its routine childhood
immunization schedule. The CDC recommended Gardasil for all girls aged
11-12 and even for girls as young as 9, with catch-up doses for girls and women
13-26 who hadn't been vaccinated earlier.
HPV is a sexually transmitted
virus, with dozens of strains.
As of December 2008, more than 23 million doses of the vaccine were
distributed, according to Souayah.
Guillain-Barre Syndrome and Vaccination: Study Details
For the study, researchers examined data from the Vaccine Adverse Event
Reporting System (VAERS), which is managed by the CDC and the FDA.
There were 53 cases of Guillain-Barre reported after HPV vaccination in the United
States from 2006 to 2008. In nearly three-fourths of cases, the disorder
developed within six weeks after vaccination. More than one-third of cases
occurred in the first two weeks.
The fact that so many cases occurred in the first few weeks after
vaccination strongly suggests that “some cases are caused by the vaccine,”