Quadrivalent Influenza Vaccine
Questions & Answers
The quadrivalent flu vaccine is designed to protect against four different flu viruses; two influenza A viruses and two influenza B viruses.
For years, flu vaccines have been trivalent, or designed to protect against three different flu viruses—two A viruses and one B virus. Experts have had to choose between two very different B viruses for that year’s flu vaccine, even though both B viruses spread in most seasons. This meant the vaccine did not help to protect against the second group of B viruses that was not included in the vaccine. By adding another B virus to the vaccine, quadrivalent vaccines may give broader protection.
There is a standard-dose quadrivalent shot that can be given to children as young as 6 months of age. Other standard-dose quadrivalent shots are approved for people 3 years and older. The standard-dose quadrivalent nasal spray vaccine is approved for healthy* people 2 through 49 years of age. Refer to the table of 2013-14 approved influenza vaccines in the U.S. for more information.
Influenza vaccine is not approved for children younger than 6 months of age.
People who have had a severe allergic reaction to influenza vaccine should generally not be vaccinated.
There are some people who should not get a flu vaccine without first consulting a physician.
- People who have a moderate-to-severe illness with or without a fever (they should wait until they recover to get vaccinated), and
- People with a history of Guillain–Barré Syndrome (a severe paralytic illness, also called GBS) that occurred after receiving influenza vaccine and who are not at risk for severe illness from influenza should generally not receive vaccine. Tell your doctor if you ever had Guillain-Barré Syndrome. Your doctor will help you decide whether the vaccine is recommended for you.
No. CDC does not recommend one flu vaccine over another. This includes deciding between trivalent or quadrivalent vaccine or between injection (the flu shot) or nasal spray vaccine. The most important thing is to get a flu vaccine every year. Talk to your doctor or nurse about the best options for you and your loved ones.
Yes. Flu vaccines that protect against four flu viruses are made in the same way as the flu vaccines that have been around for years that protect against three flu viruses. The difference is the addition of another vaccine virus. Studies have shown that vaccines made to protect against four flu viruses have a safety profile similar to seasonal flu vaccines made to protect against three viruses, with similar—mostly mild—side effects. Hundreds of millions of people have safely gotten flu vaccines that protect against three flu viruses. Like all seasonal flu vaccines, vaccines that protect against four flu viruses will be monitored for their safety and effectiveness.
Quadrivalent vaccine cannot cause influenza infection or illness. The vaccine viruses used to make it are ‘inactivated’ and are therefore not infectious.
Some quadrivalent flu vaccine will be available, but most flu vaccines will be trivalent this season. Of the 138-145 million doses of influenza vaccine projected to be available for the 2013-2014 season, manufacturers estimate that 30-32 million doses will be available as quadrivalent flu vaccines.
Don’t delay getting a flu vaccine if you want a quadrivalent vaccine and it isn’t available. Most of the flu vaccine offered this year will be trivalent. The important thing is to get vaccinated against influenza. Find flu vaccine near you using the vaccine finder at http://vaccine.healthmap.org/. Call ahead to ask about availability if you’re interested in a specific type of vaccine.
Quadrivalent flu vaccines may cost more than trivalent vaccines. Ask your insurance provider or doctor to find out how much you may need to pay and how much of the cost is covered by insurance.
(*”Healthy” indicates persons who do not have an underlying medical condition that predisposes them to influenza complications.)