Healthcare professionals have been urged to be alert for a small increased risk of Guillain-Barré syndrome following respiratory syncytial virus (RSV) vaccination in adults aged 60 years and older.
In updated advice, the Medicines and Healthcare products Regulatory Agency (MHRA) said this applies to all recipients of Abrysvo (Pfizer) and Arexvy (GSK). They advised being attentive to signs and symptoms of Guillain-Barré syndrome to ‘ensure early and correct diagnosis’ as well as initiating appropriate care and treatment.
Symptoms include tingling, numbness or pins and needles in the feet and hands, which is usually followed by muscle weakness and difficulty moving joints. Other symptoms can include nerve pain in the legs or back, breathing difficulties, drooping face muscles or trouble swallowing or speaking, and double vision. Paralysis can occur in some severe cases.
Early hospital treatment for Guillain-Barré syndrome can reduce severity and improve outcomes, the medicines regulator said, adding that the benefits of vaccination against RSV for older adults still outweigh the small risk of developing the condition.
The MHRA 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, with the latter being effective against severe RSV infection in infants.
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.
Yellow Card reports for RSV vaccine
Up to 2 June 2025, the MHRA said it had received 21 Yellow Card reports of suspected Guillain-Barré syndrome in older adults following a vaccination with Abrysvo.
The regulator is reminding healthcare professionals and patients to continue to report side effects associated with the RSV vaccine to the Yellow Card scheme.
So far, around 1.9 million doses of Abrysvo have been given as part of the older adult RSV vaccination programme.
A post-marketing observational study in the United States in older adults estimated that Abrysvo and Arexvy were associated with nine and seven excess Guillain-Barré syndrome cases per million vaccine doses administered, respectively.
Preliminary unpublished post-marketing study data from the UK Health Security Agency (UKHSA) and Public Health Scotland studies in adults aged 75-79 years estimate a combined excess of 15 to 25 Guillain-Barré syndrome cases per million vaccine doses of Abrysvo administered.
A review of the latest UK 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.
A version of this article was originally published by our sister publication Pulse.
