Influenza

Influenza can cause substantial morbidity and mortality, especially during the late fall and winter, peaking in February.38 The number of annual deaths related to influenza varies depending on the virus type and subtype, ranging from a few thousand to nearly 50,000 deaths. The Centers for Disease Control (CDC) Advisory Committee on Immunization Practices (ACIP) updates its recommendations for vaccination annually. Two types of vaccine are available: the "flu shot," an inactivated vaccine containing killed virus, and a nasal-spray vaccine containing attenuated live viruses, approved only for healthy people between the ages of 2 and 49 years. Because influenza viruses mutate from year to year, each vaccine contains three to four vaccine strains and is modified yearly. Note that annual vaccination is recommended for everyone aged ≥6 months.

Summary of 2015-2016 CDC Influenza Vaccine Recommendations—Adults

Annual vaccination is recommended for all people aged 6 months and older, especially the groups listed below.40

● Adults with chronic pulmonary and cardiovascular conditions (except hypertension) and renal, hepatic, neurologic, hematologic, or metabolic disorders (including diabetes mellitus); adults who are immunosuppressed or morbidly obese

● Adults ≥50 years of age

● Pregnant women and women up to 2 weeks postpartum

● Residents of nursing homes and long-term care facilities

● American Indians and Alaska natives

● Health care personnel

● Household contacts and caregivers of children ≤5 years of age (especially infants ≤age 6 months) and of adults ≥50 years of age with clinical conditions placing them at higher risk for complications of influenza