The U.S. Centers for Disease Control and Prevention said the
findings underscore the need for more effective weapons in the
fight against influenza, which kills between 3,000 and 50,000
people in the United States each year depending on the severity
of the flu season. "We simply need a better vaccine against
influenza, one that works better and lasts longer," CDC Director
Dr. Thomas Frieden said in a statement on Thursday. Experts
generally estimate the effectiveness of flu vaccines to be
between 50 percent and 70 percent, but this vaccine appears to
have fallen on the low side of that range. The vaccine did cut
the risk of medical visits caused by either influenza A or
influenza B by 56 percent, according to the study published in
the CDC's Morbidity and Mortality Weekly Report. It was more
effective against influenza B, protecting 67 percent of those
who were vaccinated. Against the influenza A (H3N2) strain, the
vaccine protected only 47 percent. The protective benefits of
the vaccine against influenza B w