The report also noted that there have been 2,643 lab-confirmed flu hospitalizations for this flu season so far, with an overall hospitalization rate of 9.7 per 100,000 population. The highest hospitalization rates occur in senior citizens (people over 65 years old) at 38.3 per 100,000 population, as well as very small children (ages zero to four), at 13.4 hospitalizations per 100,000 population.
In sum, more than half the country (28 states plus Puerto Rico) are reporting moderate to high levels of flu activity.
"We know that in seasons when H3 viruses predominant, we tend to have seasons that are the worst flu years, with more hospitalizations from flu and more deaths from the flu," said Frieden during the press conference. "Unfortunately, about half of the H3N2 viruses that we've analyzed this season are different from the H3N2 virus that's included in this year's flu vaccine. They are different enough that we're concerned that protection from vaccinations against these drifted H3N2 viruses may be lower than we usually see."
source: huffingtonpost.com