Felt like she had chemo brain; Blurred vision; Felt off balance; Chemo fog (later clarified as brain fog)/chemo fog/brain fog; Transient global amnesia/ Lost her memory; Severe headache; This spontaneous case was reported by a consumer and describes the occurrence of COGNITIVE DISORDER (Felt like she had chemo brain), VISION BLURRED (Blurred vision), BALANCE DISORDER (Felt off balance), FEELING ABNORMAL (Chemo fog (later clarified as brain fog)/chemo fog/brain fog), TRANSIENT GLOBAL AMNESIA (Transient global amnesia/ Lost her memory) and HEADACHE (Severe headache) in a 61-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 010A21A) for COVID-19 vaccination.     The patient's past medical history included Breast cancer (Had chemotherapy 6 years ago and was in remission) and Degenerative disc disease.    On 27-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 27-Feb-2021, the patient experienced COGNITIVE DISORDER (Felt like she had chemo brain) (seriousness criterion hospitalization), VISION BLURRED (Blurred vision) (seriousness criterion hospitalization), BALANCE DISORDER (Felt off balance) (seriousness criterion hospitalization), FEELING ABNORMAL (Chemo fog (later clarified as brain fog)/chemo fog/brain fog) (seriousness criterion hospitalization), TRANSIENT GLOBAL AMNESIA (Transient global amnesia/ Lost her memory) (seriousness criterion hospitalization) and HEADACHE (Severe headache) (seriousness criterion hospitalization). The patient was hospitalized on 28-Feb-2021 due to BALANCE DISORDER, COGNITIVE DISORDER, FEELING ABNORMAL, HEADACHE, TRANSIENT GLOBAL AMNESIA and VISION BLURRED. The patient was treated with ACETYLSALICYLIC ACID (BABY ASPIRIN) ongoing since an unknown date for Headache, at a dose of 1 dosage form. On 27-Feb-2021, TRANSIENT GLOBAL AMNESIA (Transient global amnesia/ Lost her memory) had resolved. At the time of the report, COGNITIVE DISORDER (Felt like she had chemo brain), VISION BLURRED (Blurred vision), BALANCE DISORDER (Felt off balance), FEELING ABNORMAL (Chemo fog (later clarified as brain fog)/chemo fog/brain fog) and HEADACHE (Severe headache) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 28-Feb-2021, Blood test: normal (normal) Normal. On 28-Feb-2021, Computerised tomogram: normal (normal) No stroke or seizure. On 28-Feb-2021, Magnetic resonance imaging: normal (normal) No stroke or seizure.     mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) dosing remained unchanged.       Patient also had electroencephalogram and neurologist informed her that the headaches were from her back disorder. Patient after vaccination went to her garage and exercised vigorously and lost her memory. She went to her neighbor and they called an ambulance. While in the ambulance she started to have her memory return. While in the emergency room, she remembered who she was but was admitted for testing from 28/Feb/2021 to 29/Feb/2021 No relevant concomitant medications were reported.  Company Comment: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded. However, underlying medical history of being an oncological patient in treatment and received chemotherapy could probably be contributory factors to the events.; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded. However, underlying medical history of being an oncological patient in treatment and received chemotherapy could probably be contributory factors to the events.