Introduction

Class Name(s):

• 80:12 Vaccines

Brand Name(s):

• mFlusiva^®

Why get vaccinated?

Influenza vaccine, mRNA may prevent influenza illness (flu) that may occur with infection due to the influenza virus.

Flu is a contagious disease that spreads around the United States every year, usually between October and May. Anyone can get the flu, but it is more dangerous for some people. Flu can cause fever and chills, sore throat, muscle aches, fatigue, cough, headache, and runny or stuffy nose. Flu can cause other complications such as sinus infections and pneumonia and can lead to hospitalization and death.

Influenza vaccine, mRNA does not contain the influenza virus. The vaccine works by getting the body's cells to produce a piece of the virus that will stimulate antibodies prepared to fight the virus if exposed.

There are many variants of the influenza virus and the vaccine will need to be reformulated periodically to cover the current circulating variants.

How is the vaccine given?

Influenza vaccine, mRNA comes as a suspension (liquid) to be given intramuscularly (into the muscle) by a healthcare provider.

Influenza vaccine, mRNA is given as a single dose each season.

What should you tell the person who is giving the vaccine?

Tell your vaccine provider if you:

• have had an allergic reaction to this vaccine, any part of this vaccine, any other vaccine or any drug, food or substance. Tell your vaccine provider about the allergy and what symptoms you had.
• have had a history of Guillain-Barre syndrome (an autoimmune disorder that causes numbness in the extremities, muscle pain, difficulty walking or standing, and paralysis often triggered by an infection) or have a weakened immune system due to a condition or medication you are receiving.
• are pregnant or breastfeeding.

In some cases, your health care provider may decide to postpone vaccination to a future visit.

What are the risks from vaccination?

Side effects that have been reported with [Vaccine X] include:

• pain, swelling or redness at the site of injection
• tiredness
• headache
• muscle or joint pains

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• rash, shortness of breath or difficulty breathing, swelling of face or throat
• numbness in the extremities, muscle pain, difficulty walking or standing, paralysis

People sometimes faint after medical procedures, including vaccination. Tell your provider if you feel dizzy or have vision changes or ringing in the ears.

Adverse reactions should be reported to the Vaccine Adverse Event Reporting System (VAERS). Your health care provider will usually file this report, or you can do it yourself. Visit http://vaers.hhs.gov or call 1-800-822-7967. VAERS is only for reporting reactions, and VAERS staff members do not give medical advice.

How can I learn more?

• Read the Vaccine Information Sheet (VIS) that your vaccine provider will give you or you can obtain it at http://www.cdc.gov/vaccines/hcp/current-vis/index.html
• Ask your healthcare provider.
• Call your local or state health department.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™ Copyright, 2026. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: September 15, 2026.