Shortly after getting a vaccination, people are no more likely to develop a dangerous nerve-damaging condition called Guillain-Barré syndrome, or GBS, than they are at other times, a new analysis finds.
Roger Baxter of Kaiser Permanente Northern California in Oakland, and his colleagues reviewed medical records from 1994 to 2006 of more than 3 million Kaiser members and found 415 diagnoses of GBS. Only 25 of these people had received any vaccine in the six weeks prior to being diagnosed with the condition. None were children. Analyses showed that people were no more likely to develop GBS during those six weeks than they were 1.5 to 9 months following a vaccination, the researchers report in the July 15 Clinical Infectious Diseases.
An earlier study had found an association between receiving the 1976 swine flu vaccine and increased GBS risk, but nearly all studies since then have failed to find a GBS link to flu shots or other vaccinations.
Nearly 7 million flu shots were dispensed to the Kaiser members during the study period. GBS showed up in 18 of these people in the six weeks after getting a flu shot. But 13 of them had a respiratory or gastrointestinal illness at the time, a known risk factor for GBS.