The paralyzing syndrome Guillain-Barré syndrome isn't linked to receiving common vaccines, according to a U.S. study.
Concerns about the association of Guillain-Barré syndrome with vaccines have "flourished" since there was a hint of an increased risk after the 1976 swine flu vaccine campaign. It hasn’t been clearly linked since then.
The syndrome is an acute inflammatory disease that results in destruction of a nerve’s myelin sheath and some nerves, which in severe cases can progress to complete paralysis and even death.
Researchers from the U.S. Centers for Disease Control and Prevention and Kaiser Permanente Vaccine Study Center in Oakland, Calif. looked back at cases of GBS over 13 years in the state that were confirmed by a neurologist who reviewed the medical records.
In the 13-year study period 415 patients were confirmed with GBS only 25 had received a vaccine within six weeks before onset of the disease.
"In summary, this study did not find any association between influenza vaccine or any other vaccine and development of GBS within six weeks following vaccination," Dr. Roger Baxter, co-director of the Kaiser Permanente Vaccine Study Center and his co-authors concluded in Monday's online issue of Clinical Infectious Diseases.
"Although we had limited power to fully assess the risk of GBS following vaccination due to the rarity of the outcome, the low numbers of GBS cases that were temporally associated with vaccination, coupled with our results, provide reassurance that the risk of GBS following any vaccine, including influenza vaccines, is extremely low."
Part of the difficulty in assessing the risk of the syndrome is the potential for differences between vaccinated and unvaccinated individuals that may not be measured.
The researchers also pointed to how variables like infectious diseases and vaccination rates change over time, which can be a source of confusion. Baxter's team said they used special data crunching methods to consider seasonal effects for example since more cases tend to be more common in winter months.
The study was funded by a subcontract with America's Health Insurance Plans (AHIP) under a contract from the CDC.
Baxter and one of his co-authors have received research grants from Merck & Company, Pfizer, Sanofi Pasteur, Novartis Vaccines, GlaxoSmithKline, and MedImmune.