Adjuvanted Flu Vaccine

Flu Vaccine with Adjuvant, brand names Fluad and Fluad Quadrivalent.

At a glance

  • Fluad is one three flu vaccines that are preferentially recommended for people 65 years and older
  • People ages 65 and up are at higher risk for severe illness and death from flu.
  • Fluad is a standard-dose, inactivated influenza (flu) vaccine, manufactured by Seqirus that contains an adjuvant.
  • An adjuvant is an ingredient added to a vaccine that helps create a stronger immune response to vaccination.

Overview

ACIP Recommendations‎

Prevention and Control of Seasonal Influenza with Vaccines: Recommendations of the Advisory Committee on Immunization Practices — United States, 2024-2025 Influenza Season has been published.

This page provides information on Fluad influenza vaccine.

Fluad Influenza Vaccine

Fluad is a standard-dose, inactivated influenza (flu) vaccine, manufactured by Seqirus that contains an adjuvant. Fluad is manufactured using an egg-based process (like most flu vaccines) and includes a non-aluminum adjuvant called MF59. An adjuvant is an ingredient added to a vaccine that helps create a stronger immune response to vaccination. Fluad is approved for use among people 65 years and older, who often have a lower protective immune response after flu vaccination compared to younger people.

MF59 Oil-In-Water Emulsion of Squalene Oil

MF59 is an oil-in-water emulsion of squalene oil. Squalene, a naturally occurring substance found in humans, animals, and plants, is highly purified for the vaccine manufacturing process.

Adding Adjuvants to Flu Vaccines

An adjuvant is an ingredient of some vaccines that helps promote a better immune response. Adjuvants also can reduce the amount of virus needed for production of a vaccine, which can allow for greater supplies of vaccine to be manufactured.

Approval of Fluad in other countries outside the U.S.

Fluad was initially approved in Italy in 1997, and at the time of its U.S. approval in November 2015, had been licensed in 38 countries, including Canada and 15 European countries.

Who Can Receive Fluad?

In the United States, Fluad is licensed for people 65 years and older, and is one of three vaccines that are preferred for this age group. Fluad is also an acceptable option for influenza vaccination of solid organ transplant recipients who are 18 through 64 years old and are taking immunosuppressive medications (without a preference over other age-appropriate inactivated or live vaccines).

Who Should Not Receive Fluad

Fluad should not be given to people with a history of severe allergic reaction to any flu vaccine or to vaccine ingredients other than eggs. Information about vaccine ingredients is located in package inserts from each manufacturer.

Benefits of Fluad compared to standard-dose flu vaccines without adjuvant for adults 65 years and older

Studies that have tested the ability of Fluad to promote an immune response against flu viruses (immunogenicity) found that antibody levels were comparable to levels induced by a standard-dose, egg-based vaccine without adjuvant. Recent observational studies among Medicare beneficiaries 65 years and older found that trivalent Fluad provided greater protection against flu-related hospitalizations and emergency department visits than unadjuvanted standard-dose, egg-based quadrivalent flu vaccine. Another study published in Clinical Infectious Diseases among people aged 65 years and older residing in nursing homes noted that use of Fluad was associated with a lower risk of hospitalization for pneumonia and influenza compared with standard-dose influenza vaccine.

Flu Vaccine Recommendations

There are three influenza vaccines that are preferentially recommended for people 65 years and older. These are Fluzone High-Dose Trivalent vaccine, Flublok Trivalent recombinant Influenza vaccine and Fluad adjuvanted influenza vaccine. This recommendation was based on a review of available studies which suggests that, in this age group, these vaccines are potentially more effective than standard dose unadjuvanted influenza vaccines. There is no preferential recommendation for people younger than 65 years. If none of the three influenza vaccines preferentially recommended for people 65 years and older is available at the time of administration, people in this age group should get any other age-appropriate influenza vaccine instead.

Fluad Safety

Some adverse events (which are also reported after regular flu vaccines) were reported more frequently after vaccination with Fluad than with unadjuvanted flu vaccines. The most common adverse events experienced during clinical studies were mild to moderate and were temporary, and included pain, redness at the injection site, headache, muscle aches, and malaise. A post-licensure clinical trial found that the occurrence of injection site-pain that limited or prevented activity was not higher in adults aged 65 years and older after Fluad compared with Fluzone high-dose trivalent influenza vaccines and overall safety findings were similar in the groups. In a study comparing Fluad Quadrivalent with trivalent Fluad, some of these events were slightly more common with the quadrivalent vaccine, but most were mild and resolved within a few days.

Additional Fluad Information

More information about Fluad is available on the Food and Drug Administration (FDA) web site.

See Also: Fluad Trivalent

Additional flu vaccine recommendations for people 65 years and older

Additional information about vaccines this season for people 65 years and older is available.

Importance of Flu Vaccines Tailored for Adults 65 Years and Older

People 65 years and older are at higher risk for flu-related severe illness and death. CDC research indicates that people 65 years and older account for 70 to 85 percent of flu-related deaths and 50 to 70 percent of flu-related hospitalizations each flu season. Older adults can have lower protective immune responses after flu vaccination compared to healthy young people. Lower immune responses may lead to lower vaccine effectiveness (i.e., a measure of how well the flu vaccine protects). Given the higher risk of severe flu illness and lower protective immune response after vaccination among older adults, substantial research and development have produced new flu vaccines intended to provide better protection for people in this age group.