Alleged links between vaccines and the nerve-degenerative disorder Guillain-Barré are among vaccine safety fears. The vaccine against swine flu in 1976 was linked to the syndrome. More recently, The Lancet found a correlation between the disorder and the 2009 batch of H1N1 vaccines.
What was lacking was a long-term review of data for nonpandemic vaccines. A study has taken up this task now, looking at cases at Kaiser Permanente Northern California from 1995 to 2006, a data set covering 33 million person-years. Over this period Kaiser Permanente saw 415 cases of Guillain-Barré. The autoimmune syndrome often arises after an infection, and this was picked up by the data review. Two-thirds of the cases had a documented gastrointestinal or respiratory infection in the weeks prior to developing Guillain-Barré.
Links between Guillain-Barré and vaccinations were much weaker. Vaccines were received in the 6 weeks before the onset of Guillain-Barré in 6% of cases in the Kaiser Permanente data. "The take home message is vaccines are not causing Guillain-Barré Syndrome at a rate, if at all, that would possibly make the benefits of vaccination not worthwhile," Johns Hopkins University researcher Dr. Daniel Salmon told Reuters. Salmon is a vaccine safety expert but had no role in the study.
Of the 25 people who developed Guillain-Barré after receiving a vaccine, 18 had just been immunized against flu, two against pneumonia, three against tetanus and another three against hepatitis. Kaiser Permanente has used flu vaccines from Sanofi ($SNY), Novartis ($NVS) and MedImmune in the past. More striking, the weak vaccine link was the spike in cases of Guillain-Barré during the winter. Again, this fits with earlier research. The seasonality of Guillain-Barré may mirror the rise in flu and other respiratory infections over winter.