Updated warnings for Respiratory Syncytial Virus vaccines Arexvy and Abrysvo

Summary

Arexvy and Abrysvo are newly registered vaccines against Respiratory Syncytial Virus (RSV). This infection affects the respiratory tract and can cause severe disease, particularly in very young and older people.

Safety information for both vaccines has been updated to reflect the low risk of people contracting Guillain-Barre syndrome (GBS) following vaccination. This is a disorder in which the body’s immune system damages nerve cells, causing muscle weakness and sometimes paralysis. Most people recover completely from GBS, but some serious illnesses can be fatal.

• Arexvy and Abrysvo are both approved for individuals 60 years and older to prevent lower respiratory tract disease caused by RSV.
• Arexvy is also approved for individuals aged 50 to 59 who are at increased risk for RSV infection.
• Abrysvo is also approved for pregnant women between 24-36 weeks of gestation to prevent lower respiratory tract disease in infants from birth to 6 months of age as they acquire antibodies to RSV while in the womb. This is funded under the National Immunisation Program (for women at 28-36 weeks of gestation).

Given the potential severity of RSV infection and the rarity of GBS, the benefit-risk balance remains strongly in favour of vaccination in the target groups.

What health professionals should do

Health professionals should be aware of the higher GBS risk in people following vaccination with Arexvy or Abrysvo. Patients should be warned of this possible but rare risk and encouraged to seek medical attention if they experience symptoms, as early medical care can reduce severity and improve outcomes.

According to data from the US presented in October 2024, there were an estimated 9 excess cases of GBS per million doses of Abrysvo, and an estimated 7 excess cases per million doses of Arexvy administered to individuals aged 65 years and older. Direct comparisons of excess GBS case estimates between vaccine studies or populations is not possible due to background risk factors for GBS in the populations studied.

Health professionals should be alert to signs and symptoms of GBS to ensure correct diagnosis, in order to initiate adequate supportive care and treatment, and to rule out other causes.

Symptoms of GBS include pins and needles (paraesthesia), numbness, weakness and paralysis. Typically, hands and/or feet are affected first, with symptoms progressing up the body to the legs, arms, face and muscles involved with breathing. These symptoms may progress over a few days or weeks.

Background

GBS is a condition in which the body's immune system attacks the nerves. In its most serious form, GBS is a medical emergency. Most people with the condition need treatment in a hospital.

In November 2024, the TGA conducted a focused signal investigation to review US data presented at the Advisory Committee on Immunization Practices October 2024 meeting. Given the seriousness of this adverse event, and noting that post-marketing data from the US supported an increased risk of GBS after vaccination with Abrysvo or Arexvy, we required the PIs for these products to be updated to include the risk of GBS.

Adverse events reported to us

As of 24 March 2025, the TGA had not received any reports of GBS following vaccination with Abrysvo or Arexvy in Australia.

Changes to the PI

The risk of GBS as a rare adverse event following vaccination in people aged 60 or over have been included of the Australian PIs for Abrysvo and Arexvy (sections 4.4 and 4.8).

The PIs both include similar advice that health professionals should monitor/be alert to signs and symptoms of GBS to ensure correct diagnosis, in order to initiate adequate supportive care and treatment, and to rule out other causes.

Health professionals should refer to the PI for the relevant product for more detailed information.

Relevant literature

• Australian Immunisation Handbook.
• Mayo Clinic. Guillain-Barre syndrome.
• FDA Safety Communication. FDA Requires Guillain-Barré Syndrome (GBS) Warning in the Prescribing Information for RSV Vaccines Abrysvo and Arexvy. Published 7 January 2025.
• Centers for Disease Control and Prevention. Advisory Committee on Immunization Practices. Respiratory Syncytial Virus (RSV) Vaccines – Adult. Evaluation of Guillain-Barré Syndrome (GBS) following Respiratory Syncytial Virus (RSV) Vaccination Among Adults 65 Years and Older. 23-24 October 2024. Accessed 9 January 2025.
• Centers for Disease Control and Prevention. Advisory Committee on Immunization Practices. Respiratory Syncytial Virus (RSV) Vaccines – Adult. RSV Vaccination in Adults: Work Group interpretations. 24 October 2024.

Disclaimer

Medicines Safety Update is aimed at health professionals. It is intended to provide practical information to health professionals on medicine safety, including emerging safety issues. The information in Medicines Safety Update is necessarily general and is not intended to be a substitute for a health professional's judgment in each case, taking into account the individual circumstances of their patients. Reasonable care has been taken to ensure that the information is accurate and complete at the time of publication. The Australian Government gives no warranty that the information in this document is accurate or complete and shall not be liable for any loss whatsoever due to negligence or otherwise arising from the use of or reliance on this document.

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Medicines Safety Update is written by staff from the Pharmacovigilance Branch.

• Editor: Daniel Dascombe
• Deputy Editor: Aaron Hall
• Contributors: Clare King and Rachel Hollandi