Beyfortus (Nirsevimab)
Complete patient guide for uses, dosage, side effects, and safety information
Prescription RequiredQuick Facts
What Is Beyfortus Used For?
Beyfortus is a protective medicine that helps prevent your baby from getting respiratory syncytial virus (RSV) disease during their first RSV season.
Primary Uses
Beyfortus is used to protect babies from getting respiratory syncytial virus (RSV) disease during their first RSV season. It may also be given to children less than 2 years of age who are at risk of severe RSV disease in their second RSV season.
How It Works
Nirsevimab is an antibody that blocks the protein that RSV needs to infect the body and helps stop the virus from entering and infecting human cells. RSV is a common respiratory virus that usually causes mild cold-like symptoms but can cause severe illness, including inflammation of the small airways in the lung (bronchiolitis) and pneumonia that may lead to hospitalization or even death.
Good to know: The virus is usually more common during winter (known as the RSV season), so timing of the injection is important for maximum protection.
How to Take Beyfortus
Beyfortus is given by a healthcare professional as an injection into the muscle, usually in the outer part of the thigh.
Dosage Instructions
The recommended dose depends on your child’s weight and RSV season: 50 mg (single injection) for babies weighing less than 5 kg in their first season, 100 mg for babies weighing 5 kg or more in their first season, and 200 mg (given as 2 x 100 mg injections) for children who are vulnerable to severe RSV disease in their second RSV season. If your child is having heart surgery, they may receive an extra dose after the operation.
When It’s Given
Beyfortus should be given before the RSV season, or as soon as possible after birth for children born during the RSV season.
Important: As Beyfortus is given by a healthcare professional, it’s unlikely your child will receive too much. If you’re concerned about the dose, contact your doctor immediately.
Available Tablet Strengths
Side Effects
Like all medications, this medicine can cause side effects. Most are mild and temporary, but some require medical attention.
Common Side Effects
These side effects occur relatively frequently and usually don’t require emergency care:
- Redness, swelling or pain at injection site
- Rash
- Fever
Seek immediate medical attention if you experience:
- Difficulty breathing or swallowing
- Swelling of face, lips, tongue or throat
- Severe itching with red rash or raised bumps
- Bluing of skin, lips or fingers
- Loss of muscle tone, floppy appearance
Important Warnings
There are important safety considerations before your child receives Beyfortus.
Who Should Not Take Beyfortus
Your child should not receive Beyfortus if they are allergic to nirsevimab or any of the other ingredients listed in the medicine information.
Medical Conditions to Discuss
Check with your doctor if your child has a low number of blood platelets (which help blood clotting), a bleeding problem, bruises easily, or is taking medicine to prevent blood clots. In certain chronic health conditions where too much protein is lost via urine or gut (like nephrotic syndrome or chronic liver disease), the protection level of Beyfortus may be reduced.
Allergic Reactions: Call your doctor immediately if you notice signs of allergic reaction: difficulty breathing or swallowing, swelling of face/lips/tongue/throat, or severe itching with red rash or raised bumps.
Drug Interactions
It’s not expected that Beyfortus will be affected by other medicines or affect how other medicines work, but tell your healthcare provider about all medicines your child is taking.
- Tell your doctor about all medicines, vitamins or supplements your child is taking
- Beyfortus may be given at the same time as vaccines during the same visit
Storage
Follow the instructions in the carton on how to take care of your medicine properly. Keep it where young children cannot reach it.
Overdose Information
As Beyfortus is given by a healthcare professional, it’s unlikely your child will receive too much. If you think your child has received too much, immediately phone the Poisons Information Centre (13 11 26), contact your doctor, or go to the Emergency Department at your nearest hospital, even if there are no signs of discomfort.
Frequently Asked Questions
Beyfortus should be given before the RSV season, or as soon as possible after birth for children born during the RSV season.
Beyfortus is given by a healthcare professional as an injection into the muscle, usually in the outer part of the thigh.
Call your doctor straight away or seek immediate medical help if you notice difficulty breathing, swelling of face/lips/tongue/throat, or severe itching with red rash.
Yes, Beyfortus may be given at the same time as vaccines during the same visit.
The most common side effects include redness, swelling or pain at the injection site, rash, and fever.
The dose depends on your child’s weight: 50 mg for babies under 5 kg, 100 mg for babies 5 kg or more in their first season, and 200 mg for vulnerable children in their second RSV season.
Remind any doctor, dentist or pharmacist you visit that your child has recently received Beyfortus.
Important Disclaimer
This information is intended for general educational purposes only and should not be considered medical advice. Always consult your healthcare provider or pharmacist before starting, stopping, or changing any medication.
If you think you may have a medical emergency, call your doctor or emergency services immediately.