couldn't think straight,thinking skills weren't as good; bit of passing out; felt like I was going to pass out; hit my stomach at first/it was weird, intense; it hit her head and felt like an explosion in her head. It was intense. It felt like her head was going to explode.; Her vision was going black; cannot drive; shaky,very weak and shaky in the morning; pain in the neck; After the second and third dose, her arm was sore and went across her shoulder,arm was sore [after second and booster dose]; feels like a guinea pig/totally not functional/debilitated; It took them almost 6 months to get over the experience, and now this is just starting all over again; intense nausea that hit my stomach at first, it was weird; weakness,because they ended up in bed/She felt weak and had to sit down.; This spontaneous case was reported by a consumer and describes the occurrence of MENTAL IMPAIRMENT (couldn't think straight,thinking skills weren't as good) and LOSS OF CONSCIOUSNESS (bit of passing out) in a 73-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 051F21A, 029K20A and 039K20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Migraine (she's had migraines since she was 30 years old).   On 09-Jan-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 06-Feb-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 10-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 14-Nov-2021, the patient experienced ASTHENIA (weakness,because they ended up in bed/She felt weak and had to sit down.). On an unknown date, the patient experienced MENTAL IMPAIRMENT (couldn't think straight,thinking skills weren't as good) (seriousness criterion medically significant), LOSS OF CONSCIOUSNESS (bit of passing out) (seriousness criterion medically significant), PRESYNCOPE (felt like I was going to pass out), ABDOMINAL DISCOMFORT (hit my stomach at first/it was weird, intense), HEAD DISCOMFORT (it hit her head and felt like an explosion in her head. It was intense. It felt like her head was going to explode.), VISUAL IMPAIRMENT (Her vision was going black), IMPAIRED DRIVING ABILITY (cannot drive), TREMOR (shaky,very weak and shaky in the morning), NECK PAIN (pain in the neck), PAIN IN EXTREMITY (After the second and third dose, her arm was sore and went across her shoulder,arm was sore [after second and booster dose]), FEELING ABNORMAL (feels like a guinea pig/totally not functional/debilitated), VACCINATION COMPLICATION (It took them almost 6 months to get over the experience, and now this is just starting all over again) and NAUSEA (intense nausea that hit my stomach at first, it was weird). The patient was treated with PARACETAMOL (TYLENOL [PARACETAMOL]) for Adverse event, at an unspecified dose and frequency. At the time of the report, MENTAL IMPAIRMENT (couldn't think straight,thinking skills weren't as good), LOSS OF CONSCIOUSNESS (bit of passing out), PRESYNCOPE (felt like I was going to pass out), ABDOMINAL DISCOMFORT (hit my stomach at first/it was weird, intense), HEAD DISCOMFORT (it hit her head and felt like an explosion in her head. It was intense. It felt like her head was going to explode.), VISUAL IMPAIRMENT (Her vision was going black), IMPAIRED DRIVING ABILITY (cannot drive), TREMOR (shaky,very weak and shaky in the morning), NECK PAIN (pain in the neck), PAIN IN EXTREMITY (After the second and third dose, her arm was sore and went across her shoulder,arm was sore [after second and booster dose]), FEELING ABNORMAL (feels like a guinea pig/totally not functional/debilitated), VACCINATION COMPLICATION (It took them almost 6 months to get over the experience, and now this is just starting all over again) and NAUSEA (intense nausea that hit my stomach at first, it was weird) outcome was unknown and ASTHENIA (weakness,because they ended up in bed/She felt weak and had to sit down.) had not resolved.        For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   Company comment: This case concerns a 73-year-old, female patient with no relevant medical history reported, who experienced the unexpected serious event of Mental impairment and Loss of consciousness, with concurrent non-serious events of presyncope and head discomfort, among others. The events occurred approximately at an unknown day after the booster dose of mRNA-1273 vaccine. The rechallenge was not applicable since the events happened after the third dose and no additional dosing is expected. Furthermore, Mental impairment appeared after the first or second dose, but it is not clearly stated if it had improved previous to the booster dose or not. It is stated that it was improving at the time of the report. Loss of consciousness start date was not provided. The patient also referred that It took almost 6 months to get over the experience, and now this is just starting all over again, although the specific symptoms that reappeared are not detailed (except for pain in extremity). The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Case was assessed as serious due to important medical event and medical judgement.   This case was linked to MOD-2021-409950, MOD-2021-409978 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 15-Nov-2021: Follow up received included date of birth and event was added.; Sender's Comments: This case concerns a 73-year-old, female patient with no relevant medical history reported, who experienced the unexpected serious event of Mental impairment and Loss of consciousness, with concurrent non-serious events of presyncope and head discomfort, among others. The events occurred approximately at an unknown day after the booster dose of mRNA-1273 vaccine. The rechallenge was not applicable since the events happened after the third dose and no additional dosing is expected. Furthermore, Mental impairment appeared after the first or second dose, but it is not clearly stated if it had improved previous to the booster dose or not. It is stated that it was improving at the time of the report. Loss of consciousness start date was not provided. The patient also referred that It took almost 6 months to get over the experience, and now this is just starting all over again, although the specific symptoms that reappeared are not detailed (except for pain in extremity). The benefit-risk relationship of mRNA-1273 vaccine is not affected by this report. Case was assessed as serious due to important medical event and medical judgement.