Covid could be an occasional trigger of Guillain-Barré syndrome (GBS), a study has claimed.
The auto-immune disease, which can leave patients paralysed and in crippling pain, has also been linked to coronavirus vaccines in extremely rare cases.
Coronavirus itself is not listed as a known trigger of the condition by the National Health Service, even though other infections are named.
But research of patients struck down with GBS in China, Denmark, France, Greece, Italy, the Netherlands, Spain, Switzerland, and the UK suggests there is a correlation between infection and the condition.
The study's authors emphasised that a strong association with GBS and Covid is not likely.
However, the University of Rotterdam team claimed the virus may cause a handful of infected people to develop the condition.
It did not give any rates of how rare the condition is after Covid — but it is thought to strike just one in 10,000 people who have received the AstraZeneca vaccine.
The study, published in the journal Brain, analysed profiles of 49 GBS patients who were struck down between January and May last year.
The condition, which can be triggered by flu and glandular fever, sees the immune system go haywire and start to attack nerve cells.
Covid could be an occasional trigger of Guillain-Barré syndrome (GBS), a study has claimed. Pictured: Father-of-three William Marsh, 57, was left paralysed by the condition last year but is not thought to be one of the 22 sufferers who had Covid first
Guillain–Barré syndrome is a rare disorder in which the immune system goes into overdrive and the body attack its own nerves.
Common symptoms of the rare condition include weakness and tingling in the limbs.
As patients' conditions worsen, this can lead to parts of the body — or in some cases the whole body — being paralysed.
The syndrome is rare, affecting about one in 100,000 annually in the UK and US.
Fewer than 20,000 cases are diagnosed per year in the US, according to the National Institute of Neurological Disorders and Stroke.
Doctors say it is often