Blacked out dur to severe dehydration; Felt dizzy tired and went to sleep for a period of 4 - 5 hours; Drenched in sweat; Described his urine been very dark in color, almost black-ish in a way; Projectile vomiting of food; Night sweats; Diarrhea; Given ant nausea medications; Lot of fatigue; Felt pain in his at the injection site; Pain in his lower spine and hips; chills; Blacked out dur to severe dehydration; This spontaneous case was reported by a consumer and describes the occurrence of LOSS OF CONSCIOUSNESS (Blacked out dur to severe dehydration) and DEHYDRATION (Blacked out dur to severe dehydration) in a 53-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 010A21A and 031B21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included No adverse event (No recorded medical history).   On 05-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 02-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 02-Apr-2021, the patient experienced LOSS OF CONSCIOUSNESS (Blacked out dur to severe dehydration) (seriousness criterion medically significant), DEHYDRATION (Blacked out dur to severe dehydration) (seriousness criterion hospitalization), DIZZINESS (Felt dizzy tired and went to sleep for a period of 4 - 5 hours), HYPERHIDROSIS (Drenched in sweat), CHROMATURIA (Described his urine been very dark in color, almost black-ish in a way), VOMITING PROJECTILE (Projectile vomiting of food), NIGHT SWEATS (Night sweats), DIARRHOEA (Diarrhea), NAUSEA (Given ant nausea medications), FATIGUE (Lot of fatigue), VACCINATION SITE PAIN (Felt pain in his at the injection site ), ARTHRALGIA (Pain in his lower spine and hips) and CHILLS (chills). The patient was hospitalized from 05-Apr-2021 to 06-Apr-2021 due to DEHYDRATION. On 06-Apr-2021, LOSS OF CONSCIOUSNESS (Blacked out dur to severe dehydration), DEHYDRATION (Blacked out dur to severe dehydration), DIZZINESS (Felt dizzy tired and went to sleep for a period of 4 - 5 hours), CHROMATURIA (Described his urine been very dark in color, almost black-ish in a way), VOMITING PROJECTILE (Projectile vomiting of food), DIARRHOEA (Diarrhea), NAUSEA (Given ant nausea medications), FATIGUE (Lot of fatigue), ARTHRALGIA (Pain in his lower spine and hips) and CHILLS (chills) had resolved, VACCINATION SITE PAIN (Felt pain in his at the injection site ) outcome was unknown. At the time of the report, HYPERHIDROSIS (Drenched in sweat) and NIGHT SWEATS (Night sweats) had not resolved.            Concomitant product use was not provided by the reporter.  On an unspecified date, the patient went to sleep for a period of 4 - 5 hours. Upon waking up, he was drenched in sweat. The patient's mattress, pillow and body were covered in sweat. The patient was only able to stay awake for about 2 hours and the fell back asleep for about 4 -5 hours. This cycle of being up or 2 hours and sleep for 4 - 5 hours continued throughout the weekend. By Monday (05APR2021) morning, the night sweats continued, and contacted his primary care physician, who advised him to go to the nearest emergency room. In emergency room, while diagnostic tests were undergoing. The patient's symptoms began on Friday and ended except of the night sweat which were ongoing.  Treatment for the event included anti-nausea medications.  The patient received both scheduled doses of mRNA-1273 prior to the event; therefore, action taken with the drug in response to the event is not applicable.  Very limited information regarding these events has been provided at this time. Further information has been requested.; Sender's Comments: Very limited information regarding these events has been provided at this time. Further information has been requested.