An influenza vaccine is a vaccine given with a needle, usually in the arm. Seasonal influenza shots protect against the three or four influenza viruses that research indicates will be most common during the season.
The quadrivalent inactivated influenza vaccine contain:
- Influenza A (H1N1): an A/Brisbane/02/2018
- Influenza A (H3N2): an A/South Australia/34/2019
- Influenza B: a B/Washington/02/2019
- Influenza B: a B/Phuket/3073/2013
- Different flu shots are approved for people of different ages. Everyone should get a vaccine that is appropriate for their age.
- There are inactivated influenza vaccines (IIV) that are approved for people as young as 6 months of age.
- People aged 65 years and older.
- Pregnant women and people with certain chronic health conditions can get a flu shot.
- Most people with egg allergycan get a flu shot.
- Children younger than 6 months of age are too young to get a flu shot.
- People with severe, life-threatening allergies to flu vaccine or any ingredient in the vaccine. This might include gelatin, antibiotics, or other ingredients.
CDC conducts studies each year to determine how well the influenza (flu) vaccine protects against flu illness. While vaccine effectiveness (VE) can vary, recent studies show that flu vaccination reduces the risk of flu illness by between 40% and 60% among the overall population during seasons when most circulating flu viruses are well-matched to the flu vaccine. In general, current flu vaccines tend to work better against influenza B and influenza A (H1N1) viruses and offer lower protection against influenza A(H3N2) viruses.
There are many reasons to get an influenza (flu) vaccine each year. Below is a summary of the benefits of flu vaccination, and selected scientific studies that support these benefits.
- Flu vaccinationcan keep you from getting sick with flu.
- Flu vaccination can reduce the risk of flu-associated hospitalization for children, working age adults, and older adults.
- Flu vaccination is an important preventive tool for people with chronic health conditions.
- Flu vaccination helps protect women during and after pregnancy.
- Flu vaccine can be life-saving in children.
- Flu vaccination has been shown in several studies to reduce severity of illness in people who get vaccinated but still get sick.
- Getting vaccinated yourself may also protect people around you, including those who are more vulnerable to serious flu illness, like babies and young children, older people, and people with certain chronic health conditions.
Like any medical product, vaccines can cause side effects. Side effects of the flu vaccine are generally mild and go away on their own within a few days. Common side effects from the flu shot include:
- Soreness, redness, and/or swelling from the shot
- Muscle aches
CDC recommends everyone 6 months of age and older should receive an annual flu vaccination with rare exceptions. Individuals who can’t get the flu shot include:
- Children younger than 6 months, since they are too young to get a flu shot.
- Individuals with severe, life-threatening allergies to flu vaccine or any ingredient(s) in the vaccine.
Individuals should talk with their doctor before getting the flu shot if they:
- Have had a severe allergy to eggs or any of the ingredients in the vaccine.
- Have had Guillain-Barré syndrome (GBS).
- Are not feeling well.