Guillain-Barré Syndrome Surveillance and Statistics
The Minnesota Department of Health (MDH), as part of the Centers for Disease Control and Prevention (CDC) Emerging Infections Program (EIP), is conducting enhanced surveillance for Guillain-Barré Syndrome (GBS) in order to monitor the safety of the 2009 influenza A (H1N1) monovalent vaccine. GBS surveillance began October 1, 2009. Here is a brief overview of the surveillance for the first 4 months:
- MDH has established a network with all neurologists in the state in order to identify all new cases of GBS. Personal contact is made weekly. Also, all hospital medical records departments are querying their admission and discharge records to assure no GBS cases are missed. A standardized case report form is filled out for each suspect GBS case using objective medical criteria. Information on antecedent infections and any vaccinations, including influenza A H1N1 vaccine, in the 42 days prior to onset of GBS symptoms is collected. Individual case reviews may take several weeks.
- The background rate of GBS is estimated to be 1-2 per 100,000. Due to the rare nature of the illness it is important for all of the EIP network’s data, with a population total of 45 million, to be combined together, for proper statistical interpretation.
- From October 1, 2009 to January 31, 2010, in Minnesota, 82 cases of GBS-like illness have been reported; 21 of these have been confirmed as GBS, and 14 are still under investigation. In the U.S. EIP network, there have been 134 confirmed and probable GBS cases.
- It is very likely by chance alone that some people will be diagnosed with GBS following a vaccination. As more people are vaccinated with influenza A H1N1 vaccine, the likelihood increases that someone who has GBS will also have a history of H1N1 vaccination. The goal of the surveillance program is to identify an excess of GBS related to influenza A H1N1 vaccination. To date, 9 of the 134 GBS cases had received H1N1 vaccine in the 42 days prior to onset of GBS with the vaccination-to-onset interval ranging between 1 to 33 days. CDC has closely examined these data and states “There has been no observed excess risk of GBS attributable to the H1N1 vaccine.” As the H1N1 vaccination campaign continues and expands into all age groups, continued surveillance of GBS is important.
- Other vaccine safety data collection systems also affirm the safety of the novel influenza A H1N1 monovalent vaccine.
- MDH is extremely appreciative of the work of neurologists and medical records departments in this surveillance work and will continue to closely monitor GBS.
Annual Summary Statistics
- Guillain-Barré Syndrome, 2009
Minnesota Department of Health, Disease Control Newsletter;
Annual Summary of Communicable Diseases Reported to the Minnesota Department of Health, 2009.