The Centers for Disease Control is expected to give an outlook Thursday on the 2013-2014 flu season, including what types of strains are expected this year.
Last year's flu season was one of the worst in recent years, claiming the lives of 161 children -- the highest since health officials began keeping records.
A high number of people 65 and older were also hospitalized with flu-related illness.
For the first time, this year's flu shot will protect against four of the most prevalent viruses. Manufacturers expect to produce between 135 million and 139 million doses of the influenza vaccine.
Health care professionals urge anyone older than 6 months of age to get the shot or nasal vaccine.
Seasonal flu activity begins as early as October and continues through May.