"Vaccines are OK for people with Guillain-Barré syndrome," said Dr. Roger Baxter, the lead author of the study and the co-director of the Kaiser Permanente Vaccine Study Center.

Guillain-Barré is a rare autoimmune disorder that can cause muscle weakness and paralysis.

While there is no cure, some treatments can help the symptoms.

About one to two out of every 100,000 people develop the syndrome every year.

The cause is unknown, but Baxter said there's evidence that a number of cases were related to a shot against the swine flu outbreak that occurred during the 1970s.

"A relationship to a flu vaccine is possible," Baxter said, though he added that studies on Guillain-Barré and other vaccines have not found a link.

"We don't really think that other than the 1976 swine flu vaccine that there's any connection between the two," he told Reuters Health.

In fact, recent studies have found that the flu itself might be tied to the syndrome (see Reuters Health reports of June 24, 2011 and January 28, 2009).

CDC URGES CAUTION

The Centers for Disease Control and Prevention (CDC) caution against giving a flu shot to anyone with Guillain-Barré whose disease surfaced within six weeks of a previous immunization against the flu.

The recommendation is relevant to only a very small subset of people with Guillain-Barré, but Baxter's concern is that some physicians expand it to include anyone with a history of the syndrome.

As part of a large study looking for any connection between Guillain-Barré and vaccines, Baxter and his colleagues collected medical records from 550 people with the syndrome.

All the patients had been treated at Kaiser Permanente of Northern California, and the researchers searched for any immunizations and Guillain-Barré recurrences over more than a decade.

Among this group, 279 had received at least one vaccine subsequent to their diagnosis, including 107 people who got a flu shot.

In total, the patients received nearly 1,000 vaccines, and none had a flare-up of Guillain-Barré in the two months following the shots.

Only one person had a flare-up within a year of a vaccine, and it occurred four months after receiving a combination shot for measles, mumps and rubella, according to findings published in Clinical Infectious Diseases.

There were 18 people who fell into the category targeted by the CDC's recommendations against flu immunization -- those who had originally developed the syndrome within six weeks of a flu shot -- and two of them ended up receiving a flu shot later on with no record of the syndrome recurring.

Baxter -- who along with one of his co-authors has received funding from several vaccine makers -- said that even though his results show no relationship between flu shots and Guillain-Barré flare-ups, there are still too few cases to say definitively that there's no risk.

"The problem with our study is that because there were so few of our Guillain-Barré syndrome patients who had Guillain-Barré syndrome that developed within six weeks of a flu shot, there wasn't enough data to say you can vaccinate those who got it," he said.

However, "for the vast majority of Guillain-Barré syndrome people, go ahead and get flu shots," he said.

The study was funded through the CDC.

In an emailed statement from Dr. Claudia Vellozzi, the deputy director of the Immunization Safety Office at the CDC, she said, "this study adds evidence that (Guillain-Barré syndrome) recurrence after vaccination is quite rare. It provides reassurance for people with a history of (Guillain-Barré syndrome) who would like to receive vaccinations to prevent illness."

SOURCE: bit.ly/zu4Vzt Clinical Infectious Diseases, online January 19, 2012.

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