All US individuals older than 6 months should be vaccinated annually against influenza, the US Centers for Disease Control and Prevention's (CDC) Advisory Committee on Immunization Practices (ACIP) recommended at a meeting in February.
Currently, CDC guidelines advise vaccination for persons who are at higher risk of influenza complications, including children and adolescents aged 6 months to 19 years, pregnant women, persons of any age who have chronic health conditions that increase their risks, and health care workers and individuals who share a household or provide care for persons in these high-risk groups (http://www.cdc.gov/flu/protect/keyfacts.htm). According to the CDC, about 85% of US individuals fall into one of these groups. Others who are not in a high-risk group were also encouraged to be vaccinated.
Kuehn BM. CDC Advisory Committee Recommends Nearly Universal Influenza Vaccination. JAMA. 2010;303(12):1136. doi:10.1001/jama.2010.294