More importantly, for the first time some vaccines will protect against four flu strains, instead of the typical three, she added.
This year's vaccine will protect against three strains most likely to cause the flu -- two "A" variants and one "B" strain, according to the CDC.
All nasal spray vaccine and some types of injected vaccine will also include a second influenza "B" strain, the agency noted.
For more information on flu, visit the U.S. Centers for Disease Control and Prevention.
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