After a very bad flu season, millions of people suffered extended illness and a significant portion were hospitalized. At the peak of flu season, 7.5 percent of doctor’s visits were for flu-like symptoms, which matches the severity of the 2008-2009 swine flu season.

Was the severity of this year’s season due to the particular flu strain, the poor efficacy of the vaccine or simply not enough people getting vaccinated?

Dr. Dean Blumberg from UC Davis comes back to Insight and explains why this winter has seen so many flu cases.