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Vyvgart Side Effects

Generic name: efgartigimod alfa

Medically reviewed by Last updated on Feb 7, 2024.

Note: This document contains side effect information about efgartigimod alfa. Some dosage forms listed on this page may not apply to the brand name Vyvgart.

Applies to efgartigimod alfa: intravenous solution.

Serious side effects of Vyvgart

Along with its needed effects, efgartigimod alfa (the active ingredient contained in Vyvgart) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking efgartigimod alfa:

More common

Incidence not known

Other side effects of Vyvgart

Some side effects of efgartigimod alfa may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

For Healthcare Professionals

Applies to efgartigimod alfa: intravenous solution.


The most common adverse reactions reported have included respiratory tract infections, headaches, and urinary tract infections.[Ref]


Very common (10% or more): Respiratory tract infections (33%)

In clinical trials, 33% of patients treated with this drug experienced respiratory tract infections compared to 29% of placebo patients.

Nervous system

Very common (10% or more): Headache (32%; included migraine, procedural headache)

Common (1% to 10%): Paraesthesia (included oral hypoesthesia, hypoesthesia, hyperesthesia)


Very common (10% or more): Drug antibodies (20%)

Common (1% to 10%): Neutralizing antibodies


Very common (10% or more): Below normal WBC counts (12%), below normal lymphocytes (28%), and below normal neutrophils (13%)

Below normal levels of WBCs, lymphocytes, and neutrophils were observed in patients treated with this drug (12%, 28%, and 13%, respectively) compared with placebo (5%, 19%, and 6%, respectively).


Very common (10% or more): Urinary tract infections (UTI; 10%)

In clinical trials, 10% of patients treated with this drug experienced UTI compared to 5% of placebo patients.


Frequency not reported: Hypersensitivity reactions including rash, angioedema, and dyspnea


Common (1% to 10%): Myalgia


1. Product Information. Vyvgart (efgartigimod alfa). argenx US Inc. 2022.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.