Advice on Guillain-Barré risk for adult RSV vaccine updated by MHRA

Health professionals have been urged to be alert for a small increased risk of Guillain-Barré syndrome after RSV vaccination in adults over 60 years by the Medicines and Healthcare products Regulatory Agency (MHRA).

In updated advice, the medicines regulator advised healthcare professionals to be attentive to signs and symptoms of Guillain-Barré syndrome in all recipients of Abrysvo and Arexvy to ‘ensure early and correct diagnosis’ as well as initiating appropriate care and treatment.

Early medical care for Guillain-Barré syndrome can reduce severity and improve outcomes, the MHRA said.

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But the update stressed that currently there is no evidence of an increased risk of Guillain-Barré syndrome in pregnant women following RSV vaccination.

The NHS currently offers Abrysvo to adults aged 75-79 years old and to pregnant women.

Arexvy is not currently available on the NHS but may be available privately for use in individuals aged 60 years and older, or those aged 50–59 years who are at increased risk of RSV disease.

Up to 2 June 2025, the MHRA said it has received 21 Yellow Card reports of suspected Guillain-Barré syndrome in older adults following a vaccination with Abrysvo.

So far around 1.9 million doses of Abrysvo have been given in the older adult RSV vaccination programme.

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A post-marketing observational study in the United States in older adults estimated that Abrysvo and Arexvy were associated with 9 and 7 excess Guillain-Barré syndrome cases per million vaccine doses administered, respectively.

Preliminary unpublished post-marketing study data from the UK Health Security Agency and Public Health Scotland studies in adults aged 75-79 years estimate a combined excess of 15-25 Guillain-Barré syndrome cases per million vaccine doses of Abrysvo administered.

A review of the latest data by the Commission on Human Medicines has advised that the ‘benefits of the vaccine outweigh the risk of developing Guillain-Barré syndrome in older adults’.

An analysis by the UKHSA published in The Lancet in March found a 30% drop in hospital admissions in 75 to 79-year-olds – who are eligible for the RSV vaccine – after the vaccination programme was introduced.

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This article was initially published by our sister publication Pulse.