normal side effects; flu like feelings; feeling really sick; weirdness with her legs; head didn't felt right; neurological issues; stroke like thing in her head; achy/ arm hurting; warmness on her leg; arm hurting; blood pressure was spiking; blacked out; body got really warm in the first few minutes after vaccination; something went to her brain/ didn't feel right; lost ability to stand up; Not receiving 2nd dose; This spontaneous case was reported by a consumer and describes the occurrence of LOSS OF CONSCIOUSNESS (blacked out) in a 51-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 019b21a) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No medical history was reported.  Concurrent medical conditions included Autoimmune disorder and Heart disorder. Concomitant products included PREDNISONE, MONTELUKAST, BUDESONIDE, FORMOTEROL FUMARATE (SYMBICORT), AMITRIPTYLINE, ALBUTEROL [SALBUTAMOL], HYDROXYCHLOROQUINE and DICLOFENAC for an unknown indication.    On 07-Apr-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 07-Apr-2021, the patient experienced LOSS OF CONSCIOUSNESS (blacked out) (seriousness criterion medically significant), FEELING ABNORMAL (something went to her brain/ didn't feel right) and DYSSTASIA (lost ability to stand up). 07-Apr-2021, the patient experienced FEELING HOT (body got really warm in the first few minutes after vaccination). On 08-Apr-2021, the patient experienced VACCINATION COMPLICATION (normal side effects), INFLUENZA LIKE ILLNESS (flu like feelings), MALAISE (feeling really sick), LIMB DISCOMFORT (weirdness with her legs), HEAD DISCOMFORT (head didn't felt right), NERVOUS SYSTEM DISORDER (neurological issues) and MYALGIA (achy/ arm hurting). 08-Apr-2021, the patient experienced HEAD DISCOMFORT (stroke like thing in her head). 08-Apr-2021, the patient experienced FEELING HOT (warmness on her leg), PAIN IN EXTREMITY (arm hurting) and BLOOD PRESSURE INCREASED (blood pressure was spiking). On an unknown date, the patient experienced INTENTIONAL DOSE OMISSION (Not receiving 2nd dose). The patient was treated with DILTIAZEM for Blood pressure, at an unspecified dose and frequency. At the time of the report, LOSS OF CONSCIOUSNESS (blacked out), FEELING HOT (body got really warm in the first few minutes after vaccination), FEELING ABNORMAL (something went to her brain/ didn't feel right), DYSSTASIA (lost ability to stand up), VACCINATION COMPLICATION (normal side effects), INFLUENZA LIKE ILLNESS (flu like feelings), MALAISE (feeling really sick), LIMB DISCOMFORT (weirdness with her legs), HEAD DISCOMFORT (head didn't felt right), NERVOUS SYSTEM DISORDER (neurological issues), HEAD DISCOMFORT (stroke like thing in her head), MYALGIA (achy/ arm hurting), FEELING HOT (warmness on her leg), PAIN IN EXTREMITY (arm hurting) and BLOOD PRESSURE INCREASED (blood pressure was spiking) was resolving and INTENTIONAL DOSE OMISSION (Not receiving 2nd dose) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 08-Apr-2021, Blood pressure measurement: high (High) blood pressure going up.     mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was withdrawn on an unknown date.       After 5 weeks patient was feeling better. When the patient was due for the 2nd dose of the vaccine she still had symptoms so she did not take it and her HCP told her to not get the 2nd dose in order to avoid irreversible damage.  Company Comment: This case concerns a 51-year-old female patient with no relevant medical history, who experienced the unexpected event of Loss of Consciousness. The event occurred on the same day after the first dose of mRNA-1273 (Moderna COVID-19 Vaccine). The rechallenge was not applicable since only information about the first dose was disclosed. The benefit-risk relationship of mRNA-1273 (Moderna COVID-19 Vaccine) is not affected by this report.; Sender's Comments: This case concerns a 51-year-old female patient with no relevant medical history, who experienced the unexpected event of Loss of Consciousness. The event occurred on the same day after the first dose of mRNA-1273 (Moderna COVID-19 Vaccine). The rechallenge was not applicable since only information about the first dose was disclosed. The benefit-risk relationship of mRNA-1273 (Moderna COVID-19 Vaccine) is not affected by this report.