Arexvy (respiratory syncytial virus vaccine, adjuvanted) is a vaccine that’s used to prevent respiratory syncytial virus (RSV) infection. The vaccine is given as a single injection into a muscle by a healthcare professional.

Arexvy is given to certain adults to prevent lower respiratory tract infections caused by RSV. Common RSV infections include pneumonia and bronchitis.

Arexvy is a recombinant vaccine. It contains a lab-made copy of one of the proteins found in the virus. This article describes the dosage of Arexvy, as well as its strength and how it’s given. To learn more about Arexvy, see this in-depth article.

This section describes the usual dosage of Arexvy. Keep reading to learn more.

What is Arexvy’s form?

Arexvy comes in two vials that must be mixed together before use. One vial contains the vaccine in a powder form. The other vial contains an adjuvant liquid suspension (a type of liquid mixture). The adjuvant is a chemical that helps to make the vaccine more effective.

What strength does Arexvy come in?

When the two vials are mixed together, they form 0.5 milliliters (mL) of liquid suspension. A healthcare professional will draw the liquid suspension into a syringe.

What is the usual dosage of Arexvy?

Your doctor will recommend one dose of Arexvy.

Dosage for respiratory syncytial virus

The usual Arexvy dosage is 0.5 mL given as a single injection into a muscle.

Your doctor or another healthcare professional will mix the contents from the two vials and draw the liquid suspension into a syringe. The 0.5-mL dose of Arexvy will then be injected into a muscle.

If you have questions about your Arexvy dose, talk with your doctor or pharmacist.

Below are answers to some commonly asked questions about Arexvy’s dosage.

Is Arexvy’s dosage similar to the dosage of Abrysvo?

Yes, the dosages of Arexvy and Abrysvo are similar. Both RSV vaccines are given as 0.5-mL single-dose injections into a muscle.

Both vaccines come as powders, but they’re mixed with different liquids. Arexvy is mixed with an adjuvant liquid suspension. The adjuvant is a chemical that helps boost the effect of the vaccine. In contrast, Abrysvo is mixed with sterile water.

Arexvy and Abrysvo are both recombinant vaccines designed to help prevent RSV infection in adults. Abrysvo is also used during late pregnancy to help prevent RSV infection in the newborn child for the first 6 months of life. Your doctor will prescribe the vaccine that’s right for you. To learn more about how these vaccines compare, talk with your doctor.

How long does it take for Arexvy to start working?

Arexvy is a vaccine that contains a lab-made copy of one of the proteins found in the virus. After the vaccine is injected into your body, your immune system reacts as if the vaccine were a virus.

As part of your immune system’s response to the vaccine, it will make antibodies. The antibodies are made about 2 weeks after the vaccine injection. In the future, if you’re exposed to RSV, your immune system will be able to quickly make these antibodies again to fight the real infection.

If you have other questions about what to expect after receiving the Arexvy vaccine, talk with your doctor.

The sections above describe the usual dosage provided by the manufacturer. If your doctor recommends Arexvy for you, they’ll prescribe the dosage that’s right for you.

Talk with your doctor if you have questions or concerns about Arexvy vaccine.

Here are some examples of questions you may want to ask your doctor:

  • Will one dose of Arexvy be enough to prevent RSV infection?
  • Do I need to get a dose of Arexvy every year?
  • Should my dose of Arexvy be lower if I have kidney problems?

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Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.