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.
Each year, between 10 and 20 percent of the U.S. population is infected with the virus. According to the CDC, each year between 140,000 and 710,000 people are hospitalized and between 12,00 and 56,000 people die from flu-related complications.
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. CDC estimates that since 2010, flu-related hospitalizations among children younger than 5 years ranged from 7,000 to 26,000 in the United States. Additionally, since the 2004-2005 influenza season, flu-related deaths in children reported to CDC have ranged from 37 deaths to 171 deaths per season. As of March 7, 2018, a total of 114 flu-associated pediatric deaths were reported to the CDC for the 2017-18 influenza season.
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. Children 6 months through 8 years getting vaccinated for the first time, and those who have only previously gotten one dose of vaccine, should get two doses of vaccine this season. All children who have previously gotten two doses of vaccine (at any time) only need one dose of vaccine this season.
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 flu virus and trivalent vaccines that prevent against 3 strains of flu virus. For the 2017-2018 season, CDC recommends use of inactivated flu vaccines (IIV) or the recombinant influenza vaccine (RIV). The nasal spray flu vaccine (also known as FluMist, live attenuated influenza vaccine or LAIV) was found to be ineffective against strains in recent years and should not be used this season.
Although the CDC doesn’t recommend one flu vaccine over another, there are two FDA-approved flu vaccines designed specifically for people 65 and older:
The “high dose vaccine” contains 4 times the amount of antigen as the regular flu shot. Research shows that high dose flu vaccine creates a stronger immune response (higher antibody production) than standard flu vaccine.
The adjuvanted flu vaccine (Fluad) is made with MF59 adjuvant, which is designed to help create a stronger immune response to vaccination.
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.
View the Flu Vaccine Information Statement for Inactivated or Recombinant Flu Vaccines