Guillain-Barré Syndrome and Influenza A (H1N1) 2009 Monovalent Vaccines in the U.S.

Among the vaccines associated with the onset of Guillain-Barré syndrome (GBS) are the swine influenza (A/New Jersey) vaccine of 1976–1977, oral poliovirus vaccine, and tetanus toxoid. The 1976–1977 swine influenza A vaccine was associated with a relative risk of 7 to 8 for GBS, especially within 6 weeks after vaccination, with the highest risk in weeks 2 and 3. Some uncertainty remains about the risk associated with the more recent swine influenza vaccines. A small increased risk was found in a Canadian study (JW Neurol Jul 24 2012).

To see whether influenza A (H1N1) 2009 monovalent inactivated vaccine used in the U.S. increased the risk for GBS, researchers conducted a meta-analysis of data from about 23 million vaccinated people as part of…