Influenza (flu)

Shows how influenza germs spread through the air when someone coughs

What is Influenza?
Influenza (flu) is a serious disease. It is a highly contagious viral infection of the respiratory tract (nose, throat, and lungs). Flu is spread by direct and indirect contact with an infected person. The flu usually comes on suddenly. Symptoms may include fever or feeling feverish/chills; cough; sore throat; runny or stuffy nose; muscle or body aches; headaches; fatigue; vomiting; and diarrhea.

Even healthy people can become very severely ill due to the flu. Some people are at higher risk of developing serious flu-related complications including people 65 years and older, people of any age with certain chronic medical conditions (e.g., asthma, diabetes, heart disease), pregnant women, and young children.

The Statistics
Each year, between 10 and 20 percent of the U.S. population is infected with the virus. In an average year, the seasonal flu causes anywhere between 3,300 and 48,600 deaths and 200,000 hospitalizations in the U.S.

While the majority of deaths resulting from flu occur in the elderly during a typical flu season, rates of infection are highest among children. Hospitalization rates among children less than one-year-old are similar to those of the elderly. In fact, more than 20,000 children under the age of five are hospitalized due to the flu each year. In addition, influenza kills approximately 100 American children less than five years of age every year. As of August 2017, a total of 104 flu-associated pediatric deaths were reported to the CDC for the 2016-17 influenza season.

The Vaccine
The flu vaccine is the best way to protect against the disease. The medical community recommends that everyone 6 months and older receive the flu vaccine each year. Some children 6 months through 8 years of age require two doses of influenza vaccine.

Since the flu vaccine is not approved for use in infants younger than 6 months old, the best way to protect these children is to make certain that their household contacts and caregivers are vaccinated. Additionally, since flu is more likely to cause severe illness in pregnant women than in healthy women, pregnant women should be vaccinated against influenza (in any trimester). This will help protect them against the flu, and will provide some protection to their baby after he or she is born (up to 6 months old). This recommendation is supported by the American College of Obstetricians and Gynecologists. Once the baby is born, breastfeeding will also help an infant stay healthy during flu season. Breast milk passes a mother’s antibodies to her baby, which help fight off infection. The flu vaccine is safe for pregnant women and their unborn babies.

A new vaccine is created for each flu season. A variety of influenza vaccines formulations are available for the 2017-18 flu season including quadrivalent vaccines that prevent against 4 strains of influenza and trivalent vaccines that prevent against 3 strains of influenza. The CDC’s Advisory Committee on Immunization Practices (ACIP) states that live attenuated influenza vaccine (LAIV), also known as the “nasal spray” flu vaccine and FluMist, should not be used during the 2017-18 flu season due to a lack of effectiveness.

Adults aged 65 years and older can receive the standard dose or the high-dose flu vaccine.

Antiviral Drugs
People at high risk of serious flu complications and people who are very sick with flu should get antiviral drugs. Other people may be treated with antivirals at their healthcare professional’s discretion. Treatment with antivirals works best when begun within 48 hours of getting sick.

See the complete 2017-18 Summary of Flu Vaccine Recommendations on the CDC website.