Background: Since introducing the SARS-CoV-2 vaccination, different adverse effects and complications have been linked to the vaccine. Variable neurological complications have been reported after receiving the COVID-19 vaccine, such as acute encephalopathy. Case presentation:In this report, we describe three cases previously healthy men who developed acute cerebellar and brainstem symptoms with temporal relationship to ChAdOx1 nCov-19, CSF investigations showed lymphocytic pleocytosis. They received five days of 1 gm. methylprednisolone with variable response.Discussion: Extensive workup for different causes of acute encephalopathy, including autoimmune encephalitis, was negative. Also, one patient improved dramatically after receiving methylprednisolone, supporting an immune-mediated mechanism behind his acute presentation. Accordingly, we think the COVID-19 vaccine is the only possible cause of our patient's presentation, giving the temporal relationship and the absence of other risk factors for encephalopathy. Conclusion:the clinician should be aware of the possible neurological complications of the different COVID-19 vaccines. Further research is needed to clarify the pathophysiology of such complications. Large, pooled data from observational epidemiologic studies are necessary to verify causality.

A septic meningitis caused by varicella zoster virus (VZV) reactivation was less described in the literature, Varicella-zoster virus is a neurotropic virus that remain dormant in dorsal root ganglion after primary infection, usually manifested as chickenpox which gets reactivated in immunocompromized state presented usually with vesicular rash complicated with multi-organ affection such as central nervous system. Rarely this characteristic skin rash can be absent initially requiring high clinical suspicion for diagnosis. When no skin lesions are present, a high clinical suspicion is required to reach the diagnosis. In this report we described three clinical of varicella- zoster virus reactivation presented in atypical way in terms of clinical presentation and cerebrospinal fluid analysis.