Influenza Vaccine Effectiveness Studies:

During influenza A pandemics, children and young adults are usually the most affected, comprising of almost 75% of all cases. Studying influenza vaccine effectiveness and health outcomes in this population is important so that we can find ways to improve care and prevent influenza-related deaths.

To measure vaccine effectiveness, we collected samples from patients admitted to the pediatric intensive care unit (PICU) during the flu seasons of 2010-2011 and 2011-2012. We repeated this study in the flu season of 2019-2020. These patients, from across the United States, presented with symptoms of influenza-like illness. We collected respiratory samples and clinical data from all of the patients, as well as information on their vaccination history.  The children who did not have influenza were healthy comparisons to those who did have influenza, and we also recruited control subjects from the community. Both studies found that those who were vaccinated had almost a 75% lower risk of developing a life-threatening case of influenza requiring admission to the PICU. We also discovered that the number of children hospitalized in the PICU for influenza infection who were vaccinated was overall low, even though the vaccine is the best way to prevent influenza infection. The results of the first and second study are publically available.