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Advisor: Mona Sarfaty, MD, FAAFP-Thomas Jefferson University.


The influenza A (H1N1) virus emerged in the United States in the spring of 2009, initiating a program for pandemic response and the production of the 2009 monovalent H1N1 vaccine. Despite identical manufacturing techniques and licensing requirements as the seasonal influenza vaccine, there was great public concern regarding the safety and efficacy of the novel vaccine. The Vaccine Adverse Event Reporting System (VAERS) was one of the surveillance tools enhanced by federal agencies to closely monitor the pandemic vaccine. A secondary data analysis of VAERS was conducted to assess and compare adverse events for the 2009 H1N1 vaccine and the seasonal influenza vaccines from 2007-2010. Graphs and tables were generated from VAERS data from October to January of the respective flu seasons to display trends by age, report date, and symptoms. Basic findings include: there was an increase in the number of adverse events reported to VAERS; events were reported for more children under 17 years of age for the 2009 H1N1 vaccine compared to seasonal flu; reported cases of Guillain-Barre Syndrome for 2009 H1N1 vaccine were below that of the 2009-2010 seasonal influenza vaccine; and more adverse events were related to the injection vaccines. The most frequently reported symptoms to the novel vaccine were mild and similar to adverse events from the seasonal influenza vaccine. In conclusion, the safety profile of the 2009 monovalent H1N1 vaccine, in terms of reported adverse events, is comparable to the seasonal influenza vaccine.