doctor vaccinating an elderly person with the flu vaccine


By USPPG Editorial Team | Last updated: October 2026

In the FLUAD vs FLUCELVAX decision, age does most of the work. FLUAD is an adjuvanted, egg-based flu vaccine for adults 65 and older, while FLUCELVAX is a cell-based, egg-free vaccine for everyone 6 months and older. Together, these two CSL Seqirus products can cover every age group a practice sees.

This guide compares the two side by side for the 2026-2027 season. It also explains current CDC guidance for older adults and egg allergy, along with how practices usually split their stock. When you’re ready to plan orders, members can review CSL Seqirus flu vaccine pricing.

Table of Contents

  Key Takeaways:

  • FLUAD is for adults 65 and older, whereas FLUCELVAX covers everyone 6 months and older.
  • CDC asks that adults 65 and older preferentially receive a higher dose or adjuvanted vaccine, such as FLUAD.
  • Because FLUCELVAX grows in cells, it contains no egg protein or antibiotics.
  • Egg allergy alone no longer requires an egg-free product or extra precautions, according to CDC.
  • Both vaccines are trivalent this season and ship in 0.5 mL prefilled syringes.
  • CDC recommends vaccinating in September or October, then continuing while flu circulates.

FLUAD vs FLUCELVAX at a Glance

Although both are inactivated vaccines that go in the muscle, they differ in how they’re made and who they’re for. The table below draws on the 2026-2027 prescribing information and CDC’s product table.

Feature FLUAD FLUCELVAX
Vaccine type Adjuvanted inactivated (aIIV3) Cell culture-based inactivated (ccIIV3)
Approved ages 65 and older 6 months and older
How it’s made Grown in hens’ eggs Grown in Madin Darby Canine Kidney (MDCK) cells
Adjuvant MF59 (9.75 mg squalene per dose) None
Egg protein Trace ovalbumin (up to 0.4 mcg) None
Presentation 0.5 mL prefilled syringe 0.5 mL prefilled syringe (the label also lists a 5 mL multi-dose vial with thimerosal)
Dose 0.5 mL 0.5 mL at every age
Storage 2°C to 8°C, keep from light, never freeze 2°C to 8°C, never freeze

When FLUAD Is the Right Choice

FLUAD exists for one reason: older immune systems respond less strongly to standard flu vaccines. Its MF59 adjuvant, a squalene-based oil-in-water emulsion, boosts that response. As a result, CDC lists adjuvanted vaccines among the preferred options for adults 65 and older.

For the 2026-2027 season, CDC guidance says adults 65 and older should preferentially receive a higher dose or adjuvanted vaccine. That group includes adjuvanted, high-dose and recombinant vaccines. However, CDC also stresses that if none of these is available, staff should give any other age-appropriate vaccine instead of delaying.

What to tell patients about side effects

Adjuvanted vaccines tend to cause more arm soreness than standard ones. In the FLUAD label, the most common reactions in adults 65 and older were injection site pain (25%) and tenderness (21%), followed by muscle aches (15%), fatigue (13%) and headache (13%). So a quick heads-up at check-in helps set expectations.

Handling notes

Gently shake each FLUAD syringe before use, since the vaccine should look milky white. Also keep cartons away from light. The FDA approved FLUAD under accelerated approval, so the label notes that studies have not yet confirmed clinical benefit based on efficacy.

When FLUCELVAX Is the Right Choice

FLUCELVAX works as a single product for almost everyone under 65. Because it carries an indication from 6 months onward, one SKU can cover children, teens and younger adults.

It also grows in mammalian cells rather than eggs. According to the label, FLUCELVAX contains no egg protein or antibiotics, and the prefilled syringes contain no preservative.

Children 6 months through 8 years

Every FLUCELVAX dose is 0.5 mL, regardless of age. Some young children, however, need two doses in the same season. CDC calls for two doses at least 4 weeks apart when a child 6 months through 8 years hasn’t already received at least two flu vaccine doses before July 1 of that season. Ideally, children finish both doses by the end of October.

Pregnancy data

The FLUCELVAX label summarizes a U.S. pregnancy registry of 665 women vaccinated with the earlier quadrivalent version. In that registry, rates of major birth defects and miscarriage were each 1.9%, consistent with background rates. CDC also says pregnant patients should receive an inactivated or recombinant flu vaccine, at any point in pregnancy.

Egg Allergy: What the Guidance Says Now

Older guides often steered egg-allergic patients toward egg-free vaccines. That advice is out of date. CDC now states that people 6 months and older with egg allergy may receive any influenza vaccine appropriate for their age and health. In other words, egg allergy alone needs no extra precautions beyond those for any vaccine.

Still, product labels haven’t all changed. For example, the FLUAD label lists a severe allergic reaction to any vaccine component, including egg protein, as a contraindication. For a patient with a history of severe egg allergy who is 65 or older, a clinician may therefore choose an egg-free option. Either way, document the reasoning in the chart.

How Practices Split Their Flu Stock

Most practices that carry both products use a simple rule. FLUAD goes to patients 65 and older, while FLUCELVAX covers patients from 6 months through 64. As a result, the split usually mirrors the practice’s age mix.

When you size each order, look at last season’s numbers by age band. Then add the second doses that some young children will need. Pediatric-heavy practices, for example, will lean toward FLUCELVAX, whereas internal medicine and geriatric practices will need more FLUAD.

Pre-booking usually happens months before the season. For the full planning timeline, see our flu vaccine pre-booking timeline and yearly purchasing calendar. For other vaccines older patients need, our guide to vaccines for older adults also helps.

When to Vaccinate

CDC recommends offering flu vaccine ideally in September or October. For most adults, it advises against vaccinating in July and August, unless a later visit isn’t likely. That’s because immunity may wane over the course of the season, particularly in older adults.

After October, keep going. CDC advises continuing vaccination throughout the season as long as flu viruses circulate and unexpired vaccine is available. For tips on reaching them, read our post on late-season flu vaccination.

What About AFLURIA?

Earlier versions of this guide also covered AFLURIA, CSL Seqirus’s egg-based standard-dose vaccine. However, AFLURIA does not appear in CDC’s 2026-2027 product table. So check with your USPPG representative or CSL Seqirus before you plan for it this season.

Frequently Asked Questions

What is the difference between FLUAD and FLUCELVAX?

FLUAD is an adjuvanted, egg-based flu vaccine for adults 65 and older. Its MF59 adjuvant strengthens the immune response in older adults. FLUCELVAX, by contrast, grows in mammalian cells instead of eggs and covers everyone 6 months and older. Both are trivalent for the 2026-2027 season and come in 0.5 mL prefilled syringes.

Can patients under 65 get FLUAD?

No. FLUAD carries an FDA indication for adults 65 and older only. For patients from 6 months through 64, practices can use FLUCELVAX or another age-appropriate vaccine instead. Meanwhile, CDC’s 2026-2027 product table also lists FLUAD at 65 and older.

Is FLUCELVAX egg-free?

Yes. Because manufacturers grow FLUCELVAX in Madin Darby Canine Kidney (MDCK) cells, the label states it contains no egg protein. It also contains no antibiotics. Still, CDC says people with egg allergy may receive any age-appropriate flu vaccine, so an egg-free product is a preference rather than a requirement.

Which flu vaccine does ACIP prefer for adults 65 and older?

For 2026-2027, CDC guidance says adults 65 and older should preferentially receive a higher dose or adjuvanted flu vaccine. That group includes adjuvanted vaccines such as FLUAD, along with high-dose and recombinant vaccines. However, if none is available, staff should give any other age-appropriate flu vaccine rather than skip vaccination.

Do children need two doses of FLUCELVAX?

Some do. Children 6 months through 8 years need two doses, at least 4 weeks apart, if they haven’t previously received at least two flu vaccine doses before July 1 of the season. Otherwise, one dose is enough. Each FLUCELVAX dose is 0.5 mL for every age.

When should practices give flu vaccines?

CDC says flu vaccination should ideally happen in September or October. For most adults, it advises against vaccinating in July and August, unless a later visit isn’t possible. Even so, practices should keep vaccinating as long as flu viruses circulate, because protection still helps later in the season.

To see contract details and ordering steps for FLUAD and FLUCELVAX, visit the CSL Seqirus vaccine page.

Sources

This article offers general information for healthcare providers and practice administrators. It does not replace the prescribing information or current CDC guidance, so clinical decisions should follow both. Because vaccine pricing, program availability and manufacturer contracts can change, contact USPPG for the most current program details.