Children aged 6 months up to their 19th birthday Pregnant women People 50 years of age and older People of any age with certain medical conditions, including chronic lung disease People who live in nursing homes and other long-term care facilities People who live with or care for those at high risk for complications from flu, including health care workers, household contacts of persons at high risk for complications from the flu, and caregivers of children less than 6 months of age who are too young to be vaccinated