In what Gottlieb called an "especially difficult" season, there have been 97 pediatric flu-related deaths so far.
The nation has seen some of the highest levels of flu-like illness and hospitalization rates in recent years, with elevated activity occurring in most of the country, according to the Centers for Disease Control and Prevention.
There are four types of influenza in play this year, Douglas said, and the effectiveness of the vaccine has varied depending on the type of flu. FDA researchers are working with CMS to use a large database that includes details of the influenza vaccines administered to 4 million people along with whether they were hospitalized for influenza or treated with antiviral medications for influenza-like illness. The flu shot wasn't particularly effective this year because one of the strains making people sick is hard to prevent using the vaccine, but experts say it's better than nothing.
"The major message out there is flu season is not over and make sure you get immunized", said McCall.
The deadly flu season may be showing signs of slowing down, slightly.
In a statement, he said an analysis of the data is still underway, but it may have some clues on effectiveness of cell-based and egg-based vaccines and may shed light on effectiveness of high-dose and adjuvanted version of the vaccines in seniors, as compared to standard flu vaccine.
While it will never get to 100 percent, Higa was optimistic the flu shot would improve. Add Flu Season as an interest to stay up to date on the latest Flu Season news, video, and analysis from ABC News.
And children really are more contagious than adults when they get sick. Thorough hand-washing, coughing and sneezing etiquette and getting the flu shot all help reduce the spread of the virus.
USA health officials Friday said fewer visits to the doctor the previous week - 1 out of 16 - were for fever, cough and other flu symptoms than during the previous two weeks, according to The Associated Press.
The nasal vaccine will be available for non-pregnant people between the ages of 2 and 49.