Getting an annual flu vaccine is the first and best way to protect yourself and your family from the flu. Flu vaccination can reduce flu illnesses, doctors’ visits, and missed work and school due to flu, as well as prevent flu-related hospitalizations. In 2017, a study in Pediatrics was the first of its kind to show that flu vaccination also significantly reduced a child’s risk of dying from influenza. The more people who get vaccinated, the more people will be protected from flu, including older people, very young children, pregnant women, and people with certain long-term health conditions who are more vulnerable to serious flu complications. This page summarizes information for the 2017-2018 flu season.

What’s new this flu season?

A few things are new this season:

• The recommendation to not use the nasal spray flu vaccine (LAIV) was renewed for the 2017-2018 season. Only injectable flu shots are recommended for use again this season.
• Flu vaccines have been updated to better match circulating viruses (the influenza A(H1N1) component was updated).
• Pregnant women may receive any licensed, recommended, and age-appropriate flu vaccine.
• Two new quadrivalent (four-component) flu vaccines have been licensed: one inactivated influenza vaccine (“Afluria Quadrivalent” IIV) and one recombinant influenza vaccine (“Flublok Qudrivalent” RIV).
• The age recommendation for “Flulaval Quadrivalent” has been changed from 3 years old and older to 6 months and older to be consistent with FDA-approved labeling.
• The trivalent formulation of Afluria is recommended for people 5 years and older (from 9 years and older) in order to match the Food and Drug Administration package insert.

A candidate vaccine virus (CVV) is an influenza (flu) virus that has been prepared by CDC or its public health partners for use by vaccine manufacturers to mass produce a flu vaccine. During the 2017-2018 season, for the first time, a true cell-based CVV has been approved for use in flu vaccine production for the Northern Hemisphere. Traditionally, CVVs have been produced using fertilized chicken eggs. The cell-based CVV has been used to produce the influenza A (H3N2) component of cell-based flu vaccines for the Northern Hemisphere in 2017-2018. Recombinant flu vaccines also are based on genetic sequences of recommended vaccine viruses that have not been propagated in eggs. Cell-based flu vaccines that use cell-based CVVs or genetic sequences have the potential to offer better protection than traditional, egg-based flu vaccines as a result of being more similar to flu viruses in circulation. For more information, see CDC’s Cell-Based Flu Vaccines webpage.

What flu vaccines are recommended this season?

This season, only injectable flu vaccines (flu shots) are recommended. Some flu shots protect against three flu viruses and some protect against four flu viruses.
Options this season include:

• Standard dose flu shots. Most are given into the muscle (usually with a needle, but one can be given to some people with a jet injector). One is given into the skin.
• High-dose shots for older people.
• Shots made with adjuvant for older people.
• Shots made with virus grown in cell culture.
• Shots made using a vaccine production technology (recombinant vaccine) that does not require the use of flu virus.

Live attenuated influenza vaccine (LAIV) – or the nasal spray vaccine – is not recommended for use during the 2017-2018 season because of concerns about its effectiveness.

What viruses will the 2017-2018 flu vaccines protect against?

There are many different flu viruses and they are constantly changing. The composition of U.S. flu vaccines is reviewed annually and updated as needed to match circulating flu viruses. Flu vaccines protect against the three or four viruses (depending on vaccine) that research suggests will be most common. For 2017-2018, three-component vaccines are recommended to contain:

• an A/Michigan/45/2015 (H1N1)pdm09-like virus (updated)
• an A/Hong Kong/4801/2014 (H3N2)-like virus
• a B/Brisbane/60/2008-like (B/Victoria lineage) virus

Quadrivalent (four-component) vaccines, which protect against a second lineage of B viruses, are recommended to be produced using the same viruses recommended for the trivalent vaccines, as well as a B/Phuket/3073/2013-like (B/Yamagata lineage) virus.

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.

Can I get a flu vaccine if I am allergic to eggs?

The recommendations for people with egg allergies are the same as last season.

• People who have experienced only hives after exposure to egg can get any licensed flu vaccine that is otherwise appropriate for their age and health.
• People who have symptoms other than hives after exposure to eggs, such as angioedema, respiratory distress, lightheadedness, or recurrent emesis; or who have needed epinephrine or another emergency medical intervention, also can get any licensed flu vaccine that is otherwise appropriate for their age and health, but the vaccine should be given in a medical setting and be supervised by a health care provider who is able to recognize and manage severe allergic conditions. (Settings include hospitals, clinics, health departments, and physician offices). People with egg allergies no longer have to wait 30 minutes after receiving their vaccine.

What sort of flu season is expected this year?

  It’s not possible to predict what this flu season will be like. Flu seasons are unpredictable in a number of ways. While flu spreads every year, the timing, severity, and length of the season varies from one year to another.

Will new flu viruses circulate this season?

  Flu viruses are constantly changing so it's not unusual for new flu viruses to appear each year.

Will the United States have a flu epidemic?

  The United States experiences epidemics of seasonal flu each year. This time of year is called "flu season." In the United States, flu season occurs in the winter; flu outbreaks can happen as early as October and can last as late as May. CDC says the flu season begins when certain key flu indicators (for example, levels of influenza-like illness (ILI), hospitalization and deaths) rise and remain elevated for a number of consecutive weeks. Usually ILI increases first, followed by an increase in hospitalizations, which is then followed by increases in flu-associated deaths.

When will flu activity begin and when will it peak?

  The timing of flu is very unpredictable and can vary in different parts of the country and from season to season. Most seasonal flu activity typically occurs between October and May. Flu activity most commonly peaks in the United States between December and February.

What should I do to protect myself from flu this season?

  CDC recommends a yearly flu vaccine for everyone 6 months of age and older as the first and most important step in protecting against this serious disease. People should begin getting vaccinated soon after flu vaccine becomes available, if possible by October, to ensure that as many people as possible are protected before flu season begins. However, as long as flu viruses are circulating in the community, it’s not too late to get vaccinated.

  In addition to getting a seasonal flu vaccine if you have not already gotten vaccinated, you can take everyday preventive actions like staying away from sick people and washing your hands to reduce the spread of germs. If you are sick with flu, stay home from work or school to prevent spreading flu to others.

What should I do if I get sick with the flu?

  Antiviral drugs are prescription drugs that can be used to treat flu illness. People at high risk of serious flu complications (such as children younger than 2 years, adults 65 and older, pregnant women, and people with certain medical conditions) and people who are very sick with flu (such as those hospitalized because of flu) should get antiviral drugs. Some other people can be treated with antivirals at their health care professional’s discretion. Treating high risk people or people who are very sick with flu with antiviral drugs is very important. Studies show that prompt treatment with antiviral drugs can prevent serious flu complications. Prompt treatment can mean the difference between having a milder illness versus very serious illness that could result in a hospital stay.

  Treatment with antivirals works best when begun within 48 hours of getting sick, but can still be beneficial when given later in the course of illness. Antiviral drugs are effective across all age-and risk groups. Studies show that antiviral drugs are under-prescribed for people who are at high risk of complications who get flu. This season, three FDA-approved influenza antiviral drugs are recommended for use in the United States: oseltamivir, zanamivir and peramivir.

What should I do to protect my loved ones from flu?

  Encourage your loved ones to get vaccinated. Vaccination is especially important for people at high risk for serious flu complications, and their close contacts. Also, if you have a loved one who is at high risk of flu complications and who develops flu symptoms, encourage him or her to get a medical evaluation. He or she might need treatment with influenza antiviral drugs. CDC recommends that people who are at high risk for serious flu complications who get the flu be treated with influenza antiviral drugs as quickly as possible. People who are not at high risk for serious flu complications who get the flu may be treated with influenza antiviral drugs at their doctor’s discretion. Children between 6 months and 8 years of age may need two doses of flu vaccine to be fully protected from flu. The two doses should be given at least 4 weeks apart. Your child’s doctor or other health care professional can tell you whether your child needs two doses. If your child does need two doses of vaccine to be fully protected, it is a good idea to begin the vaccination process sooner rather than later.

  Children younger than 6 months are at higher risk of serious flu complications, but are too young to get a flu vaccine. Because of this, safeguarding them from flu is especially important. If you live with or care for an infant younger than 6 months of age, you should get a flu vaccine to help protect them from flu.

  In addition to getting vaccinated, you and your loved ones can take everyday preventive actions like staying away from sick people and washing your hands to reduce the spread of germs. If you are sick with flu, stay home from work or school to prevent spreading influenza to others.

When should I get vaccinated?

  CDC recommends that people get vaccinated against flu soon after vaccine becomes available, if possible by October.

  It takes about two weeks after vaccination for antibodies to develop in the body and provide protection against the flu.

  Doctors and nurses are encouraged to begin vaccinating their patients soon after vaccine becomes available, preferably by October so as not to miss opportunities to vaccinate. Those children aged 6 months through 8 years who need two doses of vaccine should receive the first dose as soon as possible to allow time to get the second dose before the start of flu season. The two doses should be given at least four weeks apart.

What kind of vaccines are available in the United States for 2017-2018?

  A number of different private sector vaccine manufacturers produce flu vaccine for use in the United States. This season both trivalent (three component) and quadrivalent (four component) influenza vaccines will be available. Different routes of administration are available for flu vaccines, including intramuscular, intradermal, jet injector and nasal spray vaccine.

This season:
- Intramuscular (IM) vaccines will be available in both trivalent and quadrivalent formulations. (High dose vaccines, which are IM vaccines, will all be trivalent this season.)
- For people who are 18 through 64 years old, a jet injector can be used for delivery of one particular trivalent flu vaccine (AFLURIA® by bioCSL Inc.).
- Nasal spray vaccines will all be quadrivalent this season.
- Intradermal vaccine will all be quadrivalent.