It's that time of year again. Nurse practitioner Susan Benesh has the latest information about the flu shot. Here's what you need to know.
Why should people get vaccinated against the flu?
Influenza is a serious disease that can lead to hospitalization and sometimes even death. Every flu season is different, and influenza infection can affect people differently, but millions of people get the flu every year. CDC estimates that flu-related hospitalizations since 2010 ranged from 140,000 to 710,000, while flu-related deaths are estimated to have ranged from 12,000 to 56,000. During flu season, flu viruses circulate at higher levels in the U.S. population. (“Flu season” in the United States can begin as early as October and last as late as May.) An annual seasonal flu vaccine is the best way to reduce your risk of getting sick with seasonal flu and spreading it to others. When more people get vaccinated against the flu, less flu can spread through that community.
How do flu vaccines work?
Flu vaccines cause antibodies to develop in the body about two weeks after vaccination. These antibodies provide protection against infection with the viruses that are in the vaccine. The seasonal flu vaccine protects against the influenza viruses that research indicates will be most common during the upcoming season. Traditional flu vaccines (called “trivalent” vaccines) are made to protect against three flu viruses; an influenza A (H1N1) virus, an influenza A (H3N2) virus, and an influenza B virus. There are also flu vaccines made to protect against four flu viruses (called “quadrivalent” vaccines). These vaccines protect against the same viruses as the trivalent vaccine and an additional B virus.
What kinds of flu vaccines are available?
CDC recommends use of injectable influenza vaccines (including inactivated influenza vaccines and recombinant influenza vaccines) during 2016-2017. The nasal spray flu vaccine (live attenuated influenza vaccine or LAIV) should not be used during 2016-2017.
There are trivalent (three-component) and quadrivalent (four-component) flu vaccines will be available. You should contact your health care provider to determine which vaccine is best for you.
Are any of the available flu vaccines recommended over others?
For the 2016-2017 flu season, the Advisory Committee on Immunization Practices (ACIP) recommends annual influenza vaccination for everyone 6 months and older with either the inactivated influenza vaccine (IIV) or the recombinant influenza vaccine (RIV). There is no preference for one vaccine over another among the recommended, approved injectable influenza vaccines. There are many vaccine options to choose from, but the most important thing is for all people 6 months and older to get a flu vaccine every year.
Who should get vaccinated this season?
Everyone 6 months of age and older should get a flu vaccine every season. This recommendation has been in place since February 24, 2010 when CDC’s Advisory Committee on Immunization Practices (ACIP) voted for “universal” flu vaccination in the United States to expand protection against the flu to more people.
Vaccination to prevent influenza is particularly important for people who are at high risk of serious complications from influenza. Such as the very young, those over 65, individuals with respiratory diseases, people with compromised immune systems, and others. See People at High Risk of Developing Flu-Related Complications for a full list of age and health factors that confer increased risk.
When should I get vaccinated?
You should get a flu vaccine before flu begins spreading in your community. It takes about two weeks after vaccination for antibodies to develop in the body that protect against flu, so 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.
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.
Where can I get a flu vaccine?
Flu vaccines are offered in many locations, including 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. The CDC's Flu Vaccine Locator is a useful tool for finding vaccine in your area.
Why do I need a flu vaccine every year?
Yes. 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 sometimes updated to keep up with changing flu viruses.
Does flu vaccine work right away?
No. It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against influenza virus infection. That’s why it’s better to get vaccinated early in the fall, before the flu season really gets under way.
Can I get seasonal flu even though I got a flu vaccine this year?
Yes. There is still a possibility you could get the flu even if you got vaccinated. The ability of flu vaccine to protect a person depends on various factors, including the age and health status of the person being vaccinated, and also the similarity or “match” between the viruses used to make the vaccine and those circulating in the community. If the viruses in the vaccine and the influenza viruses circulating in the community are closely matched, vaccine effectiveness is higher. If they are not closely matched, vaccine effectiveness can be reduced. However, it’s important to remember that even when the viruses are not closely matched, the vaccine can still protect many people and prevent flu-related complications. Such protection is possible because antibodies made in response to the vaccine can provide some protection (called cross-protection) against different but related influenza viruses.
Vaccine Effectiveness and Benefits
How well the vaccine works can depend in part on the match between the vaccine virus used to produce the vaccine and the circulating viruses that season. CDC conducts studies each year to determine how well the influenza (flu) vaccine protects against flu illness. And while studies 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.
While how well the flu vaccine works can vary, there are many reasons to get a flu vaccine each year.
- Flu vaccination can keep you from getting sick with flu.
- Flu vaccination can reduce the risk of flu-associated hospitalization, including among children and older adults.
- Vaccine effectiveness for the prevention of flu-associated hospitalizations was similar to vaccine effectiveness against flu illness resulting in doctor’s visits in a comparative study published in 2016.
- Flu vaccination is an important preventive tool for people with chronic health conditions.
- Flu vaccination has been associated with lower rates of some cardiac (heart) events among people with heart disease, especially among those who experienced a cardiac event in the past year.
- Flu vaccination also has been associated with reduced hospitalizations among people with diabetes (79%) and chronic lung disease (52%).
- Flu vaccination helps protect women during and after pregnancy. Getting vaccinated against the flu can also protect a baby from flu after birth. (A mother can pass antibodies onto the developing baby during pregnancy.)
- A study that looked at flu vaccine effectiveness in pregnant women found that vaccination reduced the risk of flu-associated acute respiratory infection (ARI) by about one half.
- There are studies that show that vaccination of pregnant women can reduce their baby’s risk of flu illness by up to half. This protective benefit was observed for up to four months after birth.
- Flu vaccination also may make your flu illness milder if you do get sick.
- Getting vaccinated also protects 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.
Will this season’s vaccine be a good match for circulating viruses?
It’s not possible to predict with certainty which flu viruses will predominate during a given season. Over the course of a flu season, CDC studies samples of flu viruses circulating during that season by looking at their genetic and antigenic properties to evaluate how close a match there is between the viruses recommended for vaccine production and circulating viruses.
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 ‘inactivated’ and are therefore not infectious, or b) with no flu vaccine viruses at all (which is the case for recombinant influenza vaccine). The nasal spray flu vaccine does contain live viruses. 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.
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)
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. However, on rare occasions, flu vaccination can cause serious problems, such as severe allergic reactions. People who think that they have been injured by the flu shot can file a claim for compensation from the National Vaccine Injury Compensation Program (VICP).
More information about the safety of flu vaccines is available at Influenza Vaccine Safety.
Special Consideration Regarding Egg Allergy
The recommendations for vaccination of people with egg allergies were changed for 2016-2017 flu
People with egg allergies can receive any licensed, recommended age-appropriate influenza vaccine and no longer have to be monitored for 30 minutes after receiving the vaccine. People who have severe egg allergies should be vaccinated in a medical setting and be supervised by a health care provider who is able to recognize and manage severe allergic conditions.
For more information about the Influenza, see full information from CDC.