Patients being treated with immune checkpoint inhibitors (ICI) for advanced malignancy have an increased propensity of developing neuro-immune complications. With the advent of the COVID-19 pandemic there have been reported cases of TM following COVID-19 immunization. The reported infrequency of TM with both aforementioned causes makes delineating the etiology challenging.

5-day course of pulsed methylprednisolone followed by three therapeutic plasma exchanges produced minimal improvement in lower extremities strength and sensory level.

This case demonstrates the complication and symptomatology of TM in the setting of anti-PD-L1 monoclonal antibody with the co-incidental COVID-19 mRNA vaccine administration. The causal relationship between the vaccine and TM is difficult to establish due to limited data and the presence of a known inciting factor but hints at a possible exaggeration of the existing neuroinflammatory process.  Currently, CDC recommends that individuals who are moderately to severely immunocompromised receive an additional dose of an mRNA COVID-19 Vaccine (Pfizer-BioNTech or Moderna) at least 28 days after the completion of the initial mRNA COVID-19 vaccine series. Caution should be given for those patients who are on ICI therapy.