Influenza (flu) is a contagious viral infection that can cause mild to severe symptoms and complications like death. It spreads through coughing, sneezing, or touching contaminated surfaces. While symptoms vary, flu causes millions of illnesses, hundreds of thousands of hospitalizations, and tens of thousands of deaths in the US each year. The best way to prevent flu is to receive an annual flu vaccine by early fall before flu viruses begin spreading in communities. Flu vaccines are updated each year to protect against the viruses likely to circulate that season and can reduce severity and prevent complications even if not completely preventing infection. Antiviral drugs are recommended for high risk individuals and those hospitalized with flu to treat symptoms and shorten illness

1. Flu (Influenza)
Influenza (flu) is a contagious viral infection that can cause mild to
severe symptoms and life-threatening complications, including death,
even in healthy children and adults.
Influenza viruses spread mainly from one individual to another through
coughing or sneezing. Less often, they can also spread through
touching a contaminated surface and then touching the mouth, eyes, or
nose. Individuals can pass flu on to others even before their own
symptoms start and for a week or more after symptoms begin.
Burden
While the numbers vary, in the US, millions of individuals get sick,
hundreds of thousands are hospitalized, and tens of thousands die from
flu and related complications each year. Flu also affects employers and
businesses and costs an estimated $11.2 billionin direct and indirect
costs in the US annually. During the 2019-2020 flu season, flu
vaccination prevented approximately 7.5 million flu illnesses, 105,000
hospitalizations, and 6,300 deaths.
Symptoms
Flu is not just a common cold. It usually comes on suddenly, and
people with flu may have some or all of the following symptoms (think
F.A.C.T.S.):
 Fever
 Aches (muscle, body, and headaches)
 Chills
 Tiredness (fatigue)
 Sudden onset
 Cough, runny or stuffy nose, and/or sore throat
 Vomiting and diarrhea (more common in children than adults)
Prevention
The best way to prevent flu is to receive an influenza vaccination every
year. The Centers for Disease Control and Prevention (CDC)
recommends that everyone age 6 months and older get vaccinated

2. annually. Flu vaccination is especiallyimportant this year to help
protect individuals and prevent additional strain on an already
overburdened US healthcare system. The best time to get vaccinated is
in the early fall, before influenza viruses begin spreading in your
community. However, vaccination throughout the flu season is still
beneficial.
Flu vaccines are updated annually to protect against the influenza
viruses researchindicates are most likely to circulate during the
upcoming season. Flu vaccines can vary in how well they work, but
even in cases when flu vaccination does not prevent infection
completely, it can reduce the severity and duration of disease and
prevent serious complications. For more than 50 years, hundreds of
millions of individuals in the US have safely received seasonal flu
vaccines.
View ACIP Recommendations for the Prevention and Control of
Seasonal Influenza during the 2021-2022 Influenza Season
Note: On June 30, 2022, CDC adopted the Advisory Committee on
Immunization Practices (ACIP) recommendation to preferentially
recommend the use of specific flu vaccines for adults 65 years and
older, including higher dose and adjuvanted flu vaccines.
Treatment
Annual flu vaccination is the best way to prevent flu. Antiviral drugs
are not a substitute for annual flu vaccination; however, prescription
antiviral medications serve as an additional line of defense. CDC
recommends that all individuals who are hospitalized, severelyill, or at
high risk for developing serious flu-related complications should be
treated with antiviral drugs immediately if flu is suspected.
Treatment of flu with antiviral drugs can reduce influenza symptoms,
shorten the duration of illness by one to two days, and prevent serious
complications, like pneumonia. Antivirals work best when taken within
48 hours of getting sick, but may still be beneficial when given later in
the course of illness.