Chronic Inflammatory Demyelinating Polyradiculoneuropathy with Diplopia Caused by an Alternative Coronavirus Disease 2019 Vaccine.

The etiology of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) remains elusive and is believed to involve multiple contributing factors. There have been cases linking CIDP to the coronavirus disease 2019 (COVID-19) mRNA vaccine. However, there are no documented instances following alternative vaccines. We report a case of a 48-year-old woman, previously vaccinated with Pfizer-BioNTech's COVID-19 vaccine (BNT162b2), who subsequently received the Moderna mRNA-1273 vaccine. Within 2 days postvaccination, she developed diplopia and numbness in the lower limbs' distal extremities. Cerebrospinal fluid analysis exhibited protein-cell dissociation, while F-wave studies showed demyelinating activity in the bilateral tibial nerves. Given the disease's progressive nature, the patient was presumed to have CIDP and commenced steroid pulse therapy and intravenous immunoglobulin therapy. The onset of CIDP may be associated with variations in mRNA sequences and vaccine constituents.