Background Serious neurological complications of SARS-CoV-2 are increasingly being recognized . Case We report a novel case of HHV6 myelitis with parainfectious MOG-IgG in the setting of COVID-19-induced lymphopenia and hypogammaglobulinemia . The patient experienced complete neurological recovery with gancyclovir, high dose corticosteroids, and plasma exchange . To our knowledge, this is the first case of HHV6 reactivation in the central nervous system in the setting of COVID19 infection and the first case of MOG-IgG myelitis in the setting of SARS-CoV-2 and HHV6 coinfection . Conclusion Patients with neurological manifestations in the setting of COVID19-related immunodeficiency should be tested for opportunistic infections including HHV6 . Viral infection is a known trigger for MOG-IgG and therefore this antibody should be checked in patients with SARS-CoV-2 associated demyelination.