All content below is taken directly from the CDC statement: Key Facts About Seasonal Flu Vaccine: https://www.cdc.gov/flu/prevent/keyfacts.htm. Last reviewed: September 18, 2019.
1. What kinds of flu vaccines are available?
CDC recommends use of any licensed, age-appropriate influenza (flu) vaccine during the 2019-2020 influenza season. Options include inactivated influenza vaccine [IIV], recombinant influenza vaccine [RIV], or live attenuated influenza vaccine (LAIV). Different vaccines are licensed for different age groups, and some vaccines are not recommended for some groups of people. But where more than one suitable vaccine is available, no preference is expressed for any influenza flu vaccine over another.
2. When should I get vaccinated?
You should get a flu vaccine before flu viruses begin spreading in your community, since it takes about two weeks after vaccination for antibodies to develop in the body and provide protection against flu. Make plans to get vaccinated early in fall, before flu season begins. CDC recommends that people get a flu vaccine by the end of October, if possible. Getting vaccinated later, however, can still be beneficial and vaccination should continue to be offered throughout the flu season, even into January or later.
Getting vaccinated early (for example, in July or August) is likely to be associated with reduced protection against flu infection later in the flu season, particularly among older adults.
Children who need two doses of vaccine to be protected should start the vaccination process sooner, because the two doses must be given at least four weeks apart.
3. Why do I need a flu vaccine every year?
A flu vaccine is needed every season for two reasons. First, the body’s immune response from vaccination declines over time, so an annual vaccine is needed for optimal protection. Second, because flu viruses are constantly changing, the formulation of the flu vaccine is reviewed each year and updated as needed to keep up with changing flu viruses. For the best protection, everyone 6 months and older should get vaccinated annually.
4. Can the flu vaccine give me the flu?
No, a flu vaccine cannot cause flu illness. Flu vaccines that are administered with a needle are currently made in two ways: the vaccine is made either with a) flu vaccine viruses that have been killed (inactivated) and are therefore not infectious, or b) with proteins from a flu vaccine virus instead of flu vaccine viruses (which is the case for recombinant influenza vaccine). However, the viruses are attenuated (weakened), and therefore cannot cause flu illness. The weakened viruses are cold-adapted, which means they are designed to only cause infection at the cooler temperatures found within the nose. The viruses cannot infect the lungs or other areas where warmer temperatures exist.
5. What side effects can occur after getting a flu vaccine?
While a flu vaccine cannot give you flu illness, there are different side effects that may be associated with getting a flu shot or a nasal spray flu vaccine. These side effects are mild and short-lasting, especially when compared to symptoms of bad case of flu.
The flu shot: The viruses in the flu shot are killed (inactivated), so you cannot get the flu from a flu shot. Some minor side effects that may occur are:
• Soreness, redness, or swelling where the shot was given
• Fever (low grade)
• Aches
The nasal spray: The viruses in the nasal spray vaccine are weakened and do not cause severe symptoms often associated with influenza illness. In children, side effects from the nasal spray may include:
• Runny nose
• Wheezing
• Headache
• Vomiting
• Muscle aches
• Fever
In adults, side effects from the nasal spray vaccine may include:
• Runny nose
• Headache
• Sore throat
• Cough
If these problems occur, they begin soon after vaccination and are mild and short-lived. Almost all people who receive influenza vaccine have no serious problems from it.
6. Where can I get a flu vaccine?
Flu vaccines are offered in many doctor’s offices, clinics, health departments, pharmacies and college health centers, as well as by many employers, and even in some schools.
Even if you don’t have a regular doctor or nurse, you can get a flu vaccine somewhere else, like a health department, pharmacy, urgent care clinic, and often your school, college health center, or workplace.
7. Can I get seasonal flu even though I got a flu vaccine this year?
Yes. It’s possible to get sick with flu even if you have been vaccinated (although you won’t know for sure unless you get a flu test). This is possible for the following reasons:
• You may be exposed to a flu virus shortly before getting vaccinated or during the period that it takes the body to gain protection after getting vaccinated. This exposure may result in you becoming ill with flu before the vaccine begins to protect you. (Antibodies that provide protection develop in the body about 2 weeks after vaccination.)
• You may be exposed to a flu virus that is not included in the seasonal flu vaccine. There are many different flu viruses that circulate every year. A flu vaccine is made to protect against the three or four flu viruses that research suggests will be most common.
• Unfortunately, some people can become infected with a flu virus a flu vaccine is designed to protect against, despite getting vaccinated. Protection provided by flu vaccination can vary widely, based in part on health and age factors of the person getting vaccinated. In general, a flu vaccine works best among healthy younger adults and older children. Some older people and people with certain chronic illnesses may develop less immunity after vaccination. Flu vaccination is not a perfect tool, but it is the best way to protect against flu infection.
8. What protection does the flu vaccine provide if I do get sick with flu?
Some people who get vaccinated may still get sick. However, flu vaccination has been shown in some studies to reduce severity of illness in people who get vaccinated but still get sick. A 2017 study showed that flu vaccination reduced deaths, intensive care unit (ICU) admissions, ICU length of stay, and overall duration of hospitalization among hospitalized flu patients. Another study in 2018 showed that a vaccinated adult who was hospitalized with flu was 59 percent less likely to be admitted to the Intensive Care Unit than someone who had not been vaccinated. Among adults in the ICU with flu, vaccinated patients on average spent 4 fewer days in the hospital than those who were not vaccinated. In addition, it’s important to remember that flu vaccine protects against three or 4 different viruses and multiple viruses usually circulate during any one season. For these reasons, CDC continues to recommend flu vaccination for everyone 6 months and older even if vaccine effectiveness against one or more viruses is reduced.
9. What are the benefits of flu vaccination?
• Flu vaccination can keep you from getting sick with flu.
• Flu vaccination helps prevent serious medical events associated with some chronic conditions.
• 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.
10. Who should get vaccinated this season?
Everyone 6 months of age and older should get an influenza (flu) vaccine every season with rare exception. CDC’s Advisory Committee on Immunization Practices has made this recommendation since the 2010-11 influenza season.
Vaccination to prevent flu is particularly important for people who are at high risk of developing serious flu complications.
More information is available at: Who Should Get Vaccinated Against Influenza: http://bit.ly/2mriSNl.
Citation:
1. “Key Facts About Seasonal Flu Vaccine.” Centers for Disease Control and Prevention, National Center for Immunization and Respiratory Diseases. Last reviewed 18 Sept. 2019. https://www.cdc.gov/flu/prevent/keyfacts.htm.