Fluzone®/Flucelvax®/Fluarix®
Influenza Vaccine
Version 2025-04 · Last reviewed April 1, 2025 · Methodology
List Price
$20-30
With Insurance
$0 (ACA mandate)
How It Works
The flu vaccine trains the immune system to recognize influenza virus proteins before exposure. When vaccinated, the body creates antibodies and memory B cells that can rapidly mount a defense if the real virus is encountered.
Why the side effects happen
Soreness and mild flu-like symptoms after vaccination are caused by the immune system activating — not by infection. The vaccine contains inactivated or attenuated virus that cannot cause flu. Arm soreness is from the injection itself plus local immune activation.
When Will I Feel It?
Protection builds over 2 weeks after vaccination. Antibody levels peak and then gradually decline over the season.
Initial immune response activating. Not yet fully protected.
Full protection established. Antibody levels at peak.
Protection maintained through flu season, though antibody levels gradually decline.
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Common Side Effects
While taking this medication, you may experience the following common side effects. We've included tips on how to manage them.
Injection site soreness / redness
60-70%Normal immune response; apply ice for 10-20 minutes after injection
Headache
20%Usually mild; OTC pain reliever can help
Fatigue
18%Normal immune activation; usually 1-2 days
Muscle aches
15%Acetaminophen or ibuprofen can help; usually resolves in 1-2 days
Low-grade fever
10%Normal immune response; not a sign of flu infection
Nausea (LAIV intranasal)
8%Live attenuated nasal spray version; less common with injected form
Runny nose (LAIV)
20% (nasal form)Specific to the live attenuated nasal spray (FluMist), not injections
Arm soreness / difficulty moving
15%Normal; move arm frequently after injection to reduce soreness
Chills
7%Normal immune activation; usually resolves within 24-48 hours
Low appetite
5%Usually brief; eat lightly and stay hydrated
Serious Adverse Effects
- • Guillain-Barré syndrome (1-2 per million)
- • Severe allergic reaction / anaphylaxis (<1 per million)
- • Vasovagal syncope (fainting after injection)
- • SIRVA — Shoulder injury related to vaccine administration (rare, from improper technique)
Drug Interactions
Moderate Interactions (Caution)
When to Contact Your Doctor
This medication requires ongoing medical supervision. The following situations warrant a prompt conversation with your prescribing physician — do not wait for your next scheduled appointment.
Contact soon if you notice
- Guillain-Barré syndrome (1-2 per million)
- Severe allergic reaction / anaphylaxis (<1 per million)
- Vasovagal syncope (fainting after injection)
- SIRVA — Shoulder injury related to vaccine administration (rare, from improper technique)
Also discuss if you want to
- Review whether this medication is still appropriate for you
- Consider dosage adjustments based on response
- Explore lifestyle or non-drug alternatives
- Understand stopping or tapering options
- Plan monitoring labs and follow-up
In the US, call 911 or go to the nearest emergency room for severe symptoms. Poison Control: 1-800-222-1222.
FDA Adverse Event Reports
Patient-filed reports from the FDA FAERS database · refreshed daily
Community Reports
User-reported experiences — anonymous & anecdotal
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Metabolic & Lifestyle Alternatives
Lifestyle & Immune Health Strategies
Baseline immune health may support better outcomes alongside vaccination
Important context: Evidence quality varies across these approaches. Some are well-studied with randomized controlled trial data; others are based on observational or smaller studies. These interventions are not guaranteed to replace medication for all patients. Discuss with your doctor whether any of these are appropriate for your clinical situation.
Global Prescribing & Pricing
Global flu vaccination rates vary approximately 2× between countries; uptake depends on access, public trust, and healthcare system design
United States
Free–$40/mo
48% adult vaccination rate — below the WHO 75% target for elderly
Universal annual recommendation for 6 months+; voluntary with no systemic recall system
Free with most insurance; free at pharmacies
Australia
Free (NIP)/mo
75% of over-65s — strong population uptake
National Immunisation Program combines free access, GP recall letters, and pharmacist administration
Free — National Immunisation Program
United Kingdom
Free (NHS)/mo
70% of over-65s, 44% of under-65 at-risk groups
Systematic GP recall letters sent to all eligible patients; pharmacist and GP administration
Free — NHS funded
France
Free for at-risk/mo
52% of over-65s
Sécurité Sociale reimbursed; pharmacist-administered vaccination widely available
Fully reimbursed for at-risk groups
Japan
~$20–27/mo
60% of over-65s — school-based programs ended 1994
Municipal subsidies for elderly; school-based programs discontinued in 1994 after controversy
Partially subsidized for elderly
Australia achieves 75% elderly flu vaccination with a proactive recall system — GP letters sent directly to every eligible patient. The US achieves 48% despite also providing free access. The lesson: access is not the barrier; proactive outreach is.
Clinical Trials & Funding
Understanding who funds research helps contextualize results. Industry-funded trials are not automatically invalid — they undergo the same FDA review — but declared conflicts and sponsor effects are worth knowing. All linked trials can be verified on ClinicalTrials.gov.
Funding Sources
Mix of CDC/NIH and manufacturer funding. Effectiveness (VE) varies by year depending on strain match. Independent Cochrane reviews show more modest benefits than CDC estimates for healthy adults.
Declared Conflicts of Interest
CDC Advisory Committee on Immunization Practices (ACIP): some members have disclosed pharmaceutical industry connections. Manufacturer-funded VE studies show higher efficacy than government-funded independent studies.
Key Efficacy Results
Effectiveness varies 20-60% by season; average ~40-50% against influenza illness
Referenced Studies
Each study carries a Cochrane RoB-2 risk-of-bias badge — tap the badge for details.
Evidence & Transparency
Cochrane RoB-2 (Risk of Bias)
Badges reflect an editorial assessment using Cochrane's RoB-2 tool domains: randomization, intervention deviation, missing data, outcome measurement, and selective reporting. These are not certified Cochrane reviews. Learn more ↗
CMS Open Payments
Manufacturer payment disclosures are reported via the CMS Sunshine Act. Disclosure is legally required and does not imply bias or misconduct. Language uses "may," "suggests," or "appears" — never definitive clinical claims. CMS Open Payments ↗
Live Clinical Trials
Live from ClinicalTrials.gov · refreshed every 4 hours
Currently enrolling, active, and recently completed studies involving Influenza Vaccine. Data is pulled directly from the U.S. National Library of Medicine.
Recent Research
Live from PubMed · peer-reviewed literature · refreshed every 4 hours
Most recently indexed clinical trials and systematic reviews mentioning Influenza Vaccine in PubMed.
Source Documentation
Structured citations for referenced clinical trials
Each referenced trial is listed with its registry ID, funding source, and bias assessment. Use the copy button to generate a formatted citation.
| Trial | Registry ID | Cite |
|---|---|---|
| Fluzone HD vs Standard | NCT01427309 |
Bias ratings use Cochrane RoB-2 methodology. Editorial assessment — not a certified Cochrane review.
Our MethodologyMedical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Stopping This Medication Safely
The flu vaccine is a single annual dose — there is no medication to taper. Immune protection wanes over 6–12 months, which is why annual vaccination is recommended.
Never change or stop a medication without consulting your prescribing physician.
Questions for Your Doctor
Questions to Ask
- 1.Should I get the high-dose vaccine (65+)?
- 2.Is the nasal spray appropriate for my child?
- 3.Am I in a high-risk group?
- 4.When is the best time of year to get vaccinated?
Lab Tests to Request
- Vitamin D level
- Immunocompromised status check
Medical Disclaimer
The information on this page is compiled from publicly available clinical trial data, FDA prescribing information, and peer-reviewed literature. It is provided for educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations. Individual responses to medications vary. Always consult a qualified healthcare provider before starting, stopping, or changing any medication.
Frequently Asked Questions About Fluzone®/Flucelvax®/Fluarix®
- What is Fluzone®/Flucelvax®/Fluarix® used for?
- Fluzone®/Flucelvax®/Fluarix® (Influenza Vaccine) is a Vaccine manufactured by Multiple (Sanofi, Seqirus, GSK). FDA-approved indications include: Influenza prevention; Seasonal immunization.
- What are the common side effects of Fluzone®/Flucelvax®/Fluarix®?
- Common side effects of Fluzone®/Flucelvax®/Fluarix® include: Injection site soreness / redness (60-70%); Headache (20%); Fatigue (18%); Muscle aches (15%); Low-grade fever (10%).
- How much does Fluzone®/Flucelvax®/Fluarix® cost?
- Fluzone®/Flucelvax®/Fluarix® list price is approximately $20-30. With insurance it typically costs $0 (ACA mandate); without insurance approximately $15-50.
- Who funded the clinical trials for Fluzone®/Flucelvax®/Fluarix®?
- Mix of CDC/NIH and manufacturer funding. Effectiveness (VE) varies by year depending on strain match. Independent Cochrane reviews show more modest benefits than CDC estimates for healthy adults.
- How strong is the clinical evidence for Fluzone®/Flucelvax®/Fluarix®?
- Key studies: CDC VE studies, Cochrane influenza vaccine reviews. Effectiveness varies 20-60% by season; average ~40-50% against influenza illness Potential conflicts of interest: CDC Advisory Committee on Immunization Practices (ACIP): some members have disclosed pharmaceutical industry connections. Manufacturer-funded VE studies show higher efficacy than government-funded ind.
- Are there non-drug alternatives to Fluzone®/Flucelvax®/Fluarix®?
- Baseline immune health may support better outcomes alongside vaccination See the Alternatives tab for full details.
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