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​​What is Influenza​?

Influenza (also called the flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness, and at times can lead to hospitalization or death. The best way to prevent the flu is by getting a flu vaccine each year.

​Flu vaccination: 

  • Reduces hospitalization and death
  • Reduces severity of illness in hospitalized individuals
  • Reduces risks for major cardiac events
  • Protects pregnant women and their babies
  • Reduces missed work and school days
  • Reduces the impact of doctors appointments, medicines, and treatments on families and the healthcare system​

Influenza Symptoms

People who have the flu often feel some or all of these symptoms:

  • fever* or feeling feverish/chills
  • cough
  • sore throat
  • runny or stuffy nose
  • muscle or body aches
  • headaches
  • fatigue (very tired)
  • Some people may have vomiting and diarrhea, though this is more common in children than adults

*It’s important to note that not everyone with flu will have a fever.

How the Flu Spreads

Flu viruses spread mainly by droplets made when people with flu cough, sneeze, or talk. These droplets can land in the mouths or noses of people who are nearby. A person might also get flu by touching a surface or object that has flu virus on it and then touching their own mouth, eyes, or nose.

Period of Contagiousness

You may be able to pass the flu to someone else before you know you are sick, and while you are sick. Most healthy adults may infect others beginning 1 day before symptoms develop and up to 5-7 days after becoming sick. Some people, especially children and people with weakened immune systems, might be able to infect others for an even longer time.

How Serious is the Flu?

Flu is unpredictable and how severe it is can vary widely from one season to the next depending on many things, including:

  • what flu viruses are spreading
  • how much flu vaccine is available
  • when vaccine is available
  • how many people get vaccinated
  • how well the flu vaccine is matched to flu viruses that are causing illness

During a regular flu season, about 90 percent of deaths occur in people 65 years and older. 

Who Should Get the Flu Vaccine?

Everyone 6 months and older should get a flu vaccine every year by the end of October, if possible. However, getting vaccinated later is OK. Vaccination should continue throughout the flu season, even in January or later. Individuals traveling should get vaccinated at least 2 weeks before travel as it takes 2 weeks for vaccine immunity to develop after vaccination. Some children who have received flu vaccine previously and children who have only received one dose in their lifetime, may need two doses of flu vaccine. 

It is especially important for certain individuals to get vaccinated. These include:

  • Individuals who are at a high risk of developing serious complications like pneumonia if they get sick with the flu.
  • Individuals who have certain medical conditions including asthma, diabetes, and chronic lung disease
  • Pregnant women
  • Individuals 65 years and older
  • Indviduals who live with or care for others who are high risk of developing serious complications, for example individuals with certain medical conditions including asthma, diabetes, and chronic lung disease.
  • Health care providers
  • Parents or caregivers of children younger than 6 months, who are too young to be vaccinated

The Vaccine is NOT Recommended for: 

  • People with COVID-19 infection. Check with your doctor. 
  • Children younger than 6 months
  • People who have had Guillain-Barré syndrome (GBS) within 6 weeks of getting a flu vaccine