If someone develops Guillain-Barré Syndrome after getting their H1N1 flu shot, will the vaccine be pulled?
Based on the background rates, about 12 to 14 new cases of Guillain-Barré Syndrome (GBS) occur every week in Canada. These cases would happen regardless of the immunization campaign. A single case of GBS will not be a reason to halt the campaign. The efforts to monitor every case of GBS that occurs from the time the pandemic vaccine campaign starts, until several months after it is over will allow an assessment of whether the observed rate of disease is higher than what is expected in the population. Should the observed rate exceed what is expected then the public health response will be rapid and intense with a thorough investigation and consideration given to changing recommendations for immunization.
