From Medscape Medical News
September 23, 2009 (Düsseldorf, Germany) — Investigators have identified cases of autoimmune disorders after immunization with the quadrivalent vaccine Gardasil. The Merck product is designed to prevent infection with several types of human papillomavirus.
Presenting here at the 25th Congress of the European Committee for Treatment and Research in Multiple Sclerosis, researchers emphasized that they have not established a causal relationship between the vaccine and autoimmune problems but would like clinicians to monitor patients for any emerging adverse effects.
Two groups presented on this subject at the meeting: one identified a case of multiple sclerosis after vaccination, and the second a case of neuromyelitis optica. The studies reportedly received no outside funding.
"We will need to determine whether the incidence of autoimmune disorders is the same in the general population as in those who are vaccinated," lead investigator Maria Bouktsi from the Interbalkan European Medical Center in Thessaloniki, Greece, said in an interview.
Dr. Bouktsi pointed out this is especially important considering that the primary population for vaccination is young females and that many are already at increased risk for multiple sclerosis.
Dr. Bouktsi and her team are questioning whether the immuno-stimulatory properties of the human papillomavirus–like particles of the vaccine are triggering adverse effects in vulnerable patients.
It is the same question that researchers asked in a recent issue of Multiple Sclerosis (2009;15:116–119). Ian Sutton, MD, from St. Vincent's Hospital in New South Wales, Australia, and his team reported 5 patients who developed multiple sclerosis after vaccination with Gardasil. The group reported in January that patients presented with multifocal or atypical demyelinating syndromes within 21 days of immunization.
Causal Relationship Not Established, but Link Worth Investigating
No definitive conclusions can be made based on this report, Dr. Sutton and his team noted. "It should not be overlooked that several epidemiological studies indicate that viral infection is associated with a threefold increase in the risk of a multiple sclerosis relapse," write the researchers.
Lead investigator of the second group presenting on this topic at the meeting told Medscape Neurology he agrees that postmarketing pharmacosurveillance is necessary to improve safety. "Human papillomavirus vaccines elicit a strong inflammatory systemic immune response," said Til Menge, MD, from Heinrich-Heine University in Düsseldorf, Germany.
His group suggests that it was this inflammatory response that may have triggered a case of fulminant neuromyelitis optica in a previously healthy 17-year-old girl.
Researchers suggest data are insufficient to justify making firm recommendations regarding treatment of patients with multiple sclerosis.
Dr. Bouktsi added, "A prospective case-control study of patients with multiple sclerosis or clinically isolated demyelinating syndromes receiving the Gardasil vaccine may provide relevant safety data in this population."
The researchers have disclosed no relevant financial relationships.
European Committee for Treatment and Research in Multiple Sclerosis: Poster 308 and 514. Presented September 10 and 11, 2009.