The U.S. Centers for Disease Control and Prevention announced Thursday that the 2015 flu vaccine is better than last year's because it can protect people from more flu virus strains, Health Day reported.
Last year, the U.S. experienced a severe flu season because the vaccine was not prepared for the influenza A H3N2 strain, which was not detected early enough to be included in the vaccine. The H3N2 strain became the most predominant strain for the season, rendering the 2014 vaccine only 13 percent effective.
Researchers determine how effective a vaccine is by comparing the number of people who got sick in spite of vaccination with the number of people who got sick without vaccination, Live Science reported.
Last year's flu season killed 145 children, and there may be more unreported flu death cases, says CDC director Dr. Tom Frieden. Aside from that, "more seniors were hospitalized" because of the flu compared to previous years, Health Day reported.
This year, the CDC is predicting the 2015 flu vaccine will be 50 to 60 percent effective because it includes the H3N2 strain. However, Frieden noted that in spite of the vaccine, "millions of Americans will get the flu, hundreds of thousands will be hospitalized and thousands will die."
Fewer than half of Americans get an annual flu immunization, even though the CDC says on average, flu kills about 24,000 people a year in the U.S., according to the Associated Press.
The agency emphasized it is still not possible to determine which flu virus strain will be predominant this year.
"It is not possible to predict which influenza virus will predominate or how severe influenza-related disease activity will be during the 2015-16 season, nor is it possible to say with certainty how effective the influenza vaccine will be," the CDC said in a report. "However, laboratory analysis of influenza viruses to date suggests that the majority of viruses circulating worldwide in the past few months are similar to 2015-16 vaccine viruses."
The CDC urges the people to to vaccinated, saying it is the best way to prevent catching the flu or passing the virus to others. An estimated 171 million to 179 million flu vaccine doses will be available this year, according to Los Angeles Times.
