How Common Are Neuromuscular Disorders Following COVID-19 Vaccination?

Researchers assessed patients who developed a new-onset neuromuscular disorder the first 6 weeks after receiving either the first or second dose of the COVID-19 vaccine.

Within weeks of vaccination for COVID-19, the development of neuromuscular disorders such as Guillain-Barré syndrome (GBS) and peripheral neuropathies may develop due to a close temporal association. However, a casual relationship remains to be proven. These are the findings of 8 case studies described in Acta Neurologica Belgica.

Neuromuscular complications in close temporal relation with COVID-19 have been reported, specifically, GBS. Viral myositis, mononeuritis multiplex, and critical illness myopathy are among the other neuromuscular disorders. Following the administration of COVID-19 vaccines, including BNT162b2 (Pfzer-BioNTech), ChAdOx1 nCoV-19 (AstraZeneca) and Ad26. COV2.S (Janssen), several case reports of GBS were published. Of particular interest, 2 case series reported the onset of GBS with bifacial weakness with paraesthesia of limbs after COVID-19 vaccination.

The objective of the current study was to assess 8 patients who developed a new-onset neuromuscular disorder following COVID-19 vaccination.

Clinical researchers working at 2 different care centers in Belgium observed a pattern of new-onset neuromuscular disorders developing in 8 patients within 1 to 4 weeks of either the first or second dose of the COVID-19 vaccination.

Four COVID-19 vaccines — Pfizer-BioNTech, Moderna, Janssen, and AstraZeneca — were offered to people in Belgium when this study was conducted. Six of the patients received the Pfizer mRNA vaccine, while the remaining 2 received the AstraZeneca vaccine.

The clinicians performed thorough clinical evaluations of each patient including sensory, reflex, and muscle strength testing. Following clinical examination, the clinicians referred each of the patients to receive further specific diagnostic tests, including nerve conduction studies (NCS), magnetic resonance imaging (MRI), lumbar punctures to assess the cerebrospinal fluid (CSF) for albuminocytological dissociation, blood tests to determine serum ganglioside antibodies, and infectious disease screening.

The final neuromuscular disorder diagnoses included 2 cases of subacute-onset chronic inflammatory demyelinating polyneuropathy (CIDP), 3 cases of acute inflammatory demyelinating polyneuropathy (AIDP) with one specified as GBS, 2 case of brachial plexopathy, 1 case of subacute axonal sensorimotor polyneuropathy, and 1 case which was a variant of GBS with bifacial weakness.

The patients received treatments as tolerated including intravenous immunoglobulins (IVIG), oral methylprednisolone, and azathioprine. One patient did not receive any treatment due to mild complaints and natural stabilization of symptoms.

Most patients recovered with only mild residual sensory complaints or motor weakness at the time of the last clinical follow-up. One patient recovered fully, while another patient was receiving ongoing IVIG treatment due to fluctuating improvements and deteriorations in status.

“These various presentations strengthen the association between COVID-19 vaccination and particular GBS phenotypes,” the researchers noted. They added, “While a causal relationship between these disorders and the vaccine cannot be proven at present, the temporal association is remarkable.”


Leemans W, Antonis S, De Vooght W, Lemmens R, Van Damme P. Neuromuscular complications after COVID‑19 vaccination: a series. Acta Neurol Belg. Published online May 2, 2022. doi:10.1007/s13760-022-01941-0