2024-2025 Flu Season: Influenza Vaccine Choices

The 2024- 2025 flu season is here. The U.S. Centers for Disease Control (CDC) recommends getting your flu vaccine in September or October. Vaccine choices will be the same as last season; however ALL influenza vaccines will be trivalent instead of quadrivalent. One flu strain, the "Yamagata" strain, has not been detected in the population since 2020, so it was removed from this year's infuenza vaccines. This year's strains include  influenza A(H1N1), influenza A (H3N2), and influenza B (Victoria lineage). Note that the inflluenza A H5N1 Avian (bird flu) influenza strain is NOT covered by this year's vaccines.

Two high-strength vaccines for seniors over 65, an egg-free variety called Flucelvax for age 6 months and up, an egg-free "recombinant" vacccine called Flublok for age 18 and up, and nasal mist FluMist will be available, along with traditional quadrivalent vaccines. The CDC reports that for the 2024-2025 season, manufacturers have projected they will provide as148 million doses of influenza vaccine for the U.S. market. 

Special vaccine options available for seniors age 65 and up:

For the 2024-2025 flu season, besides regular flu shot options, two shots are again available specifically for seniors who prefer a vaccine that offers extra protection, as well as a third "recombinant" (egg free) option. The CDC does not recommend one of these vaccines for seniors over the other. A study involving 750 senior-aged adults led by Duke University compared the side effects of Fluzone High Dose with Fluad.  Clinical trials  data indicated that Fluzone High Dose had a higher incidence of temporary, local reactions, such as redness and swelling, than did Fluad. But the analysis of the study, published in JAMA Network Open, says that results support using either vaccine to prevent influenza in older adults. In addition to Fluzone High Dose and Fluad, the CDC recommends recombinant vaccine Flublok for seniors.

1.      the "high dose" flu shot (Fluzone High Dose) has four times the amount of antigen than is present in a regular vaccine. Read more about the vaccine on the Fluzone High Dose CDC information page.
This vaccine has been available since 2009. Some adverse events (which are also reported after regular flu vaccines) were reported more frequently after vaccination with Fluzone High-Dose than after standard-dose inactivated influenza vaccines.

2.      the "adjuvanted" flu vaccine (Fluad) has an extra ingredient (an oil-in-water emulsion of squalene oil) called MF59, which helps create a stronger immune response.  Read more about the vaccine on the Fluad CDC information page.
This vaccine was approved in November 2015, and was first available in the U.S. during the 2016-2017 flu season.
Some adverse events (which are also reported after regular flu vaccines) were reported more frequently after vaccination with FLUAD. 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.

3.     the "recombinant" flu vaccine (Flublok) is approved for everyone 18 and older, but also is recommended by the CDC for age 65 and up.

More highlights about vaccines offered this flu season:

- In October 2021, the FDA expanded the age indication for Flucelvax to include children age 6 months and up.

- FluMist intranasal spray is available for patients age 2 - 49 and is the only option this season if you do not want an intra-muscular shot or the jet injection. The prefilled dosage is .2mL for this vaccine.

- The Jet injector version of Afluria is available again for this flu season for those avoiding needles. PharmaJet® Stratis® Needle-Free Injection System is available for age 18 through 64 years. Afluria is also available using a regular intramuscular injection.

- Special lower-dose versions for babies: Afluria and Fluzone have half the dosage (.25mL) options for age 6 months to 36 months. Other products approved for age 6 months and up have the regular .5mL dose. Most of the flu vaccines will be preservative-free in the 2024-2025 season; only those stored in multi-use vials (such as multi-use vials of Fluzone quadrivalent, Afluria quadrivalent, and Flucelvax quadrivalent) contain the preservative thimerosal. Check with your flu shot provider to find out if yours comes in a prefilled syringe (no preservative) or multi-dose vial (will contain a small amount of thimerosal preservative).

- Most people have no or very minor side effects from their flu shot. Some might have the minor effect of a slightly stuffy nose after receiving the live nasally administered vaccine. Other people might have a preference for one type of vaccine (for example an egg-free version) over another. Minor side effects, such as sore arm, might be more severe with high dose or adjuvanted versions compared with a regular flu shot.

Not sure if you have COVID-19 or the flu?
The FDA has approved tests that can differentiate between the two illnesses: https://www.fda.gov/news-events/press-announcements/coronavirus-covid-19-update-fda-authorizes-additional-covid-19-combination-diagnostic-test-ahead-flu

Use this table to link to add or read ratings and reviews:

- FDA Information on the 2024-2025 Supply of Trivalent Influenza Vaccines: https://www.fda.gov/vaccines-blood-biologics/lot-release/use-trivalent-influenza-vaccines-2024-2025-us-influenza-season

- Vaccine supply updates from the CDC: https://www.cdc.gov/flu/prevent/vaxsupply.htm

- CDC Information on Flublock recombinant synthetic vaccine technology: https://www.cdc.gov/flu/prevent/qa_flublok-vaccine.htm and https://www.cdc.gov/flu/prevent/how-fluvaccine-made.htm#recombinant

- Presentation on Flucelvax and the decision to lower the indicated age from 4 years to 6 months by the Advisory Committee on Immunization Practicesbr>Source: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-10-20-21/03-influenza-grohskopf-508.pdf

- Vaccine Adverse Event Reporting System: https://vaers.hhs.gov/reportevent.html
VAERS is co-managed by the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA).

- September 20, 2024 CDC Update on H5N1 Bird Flu Response. Reports that 14 human cases have been detected so far. Four of these H5N1 bird flu cases were associated with exposure to sick dairy cows and nine were associated with exposure to avian influenza A(H5N1) virus-infected poultry. The other one, reported in Missouri, is still being investigated.