agonizing pain; swelling; almost fainted; has trouble walking; feet are very painful; woke up gasping for air/her breathing has not been the same/her breathing has not been the same; oxygen was down to 86-87; brain fog; keeps forgetting things; this situation is impacting her daily life; joint pain/still has joint pain; daily headache; felt really nauseous; pain in the injection site.; hives on neck/hives on upper back/hives on the neck/completely covered with hives/diagnosed her with chronic hives.; flu like symptoms; This spontaneous case was reported by an other health care professional and describes the occurrence of URTICARIA (hives on neck/hives on upper back/hives on the neck/completely covered with hives/diagnosed her with chronic hives.), PAIN (agonizing pain), SWELLING (swelling), PRESYNCOPE (almost fainted) and GAIT DISTURBANCE (has trouble walking) in a 43-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 034S21H, 043I20A and 025L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concomitant products included FLUTICASONE PROPIONATE, SALMETEROL XINAFOATE (ADVAIR) and HYDROXYZINE for an unknown indication.   On 31-Dec-2020, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 28-Jan-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 12-Nov-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In November 2021, the patient experienced URTICARIA (hives on neck/hives on upper back/hives on the neck/completely covered with hives/diagnosed her with chronic hives.), INFLUENZA LIKE ILLNESS (flu like symptoms) and VACCINATION SITE PAIN (pain in the injection site.). On an unknown date, the patient experienced PAIN (agonizing pain), SWELLING (swelling), PRESYNCOPE (almost fainted), GAIT DISTURBANCE (has trouble walking), PAIN IN EXTREMITY (feet are very painful), DYSPNOEA (woke up gasping for air/her breathing has not been the same/her breathing has not been the same), OXYGEN SATURATION DECREASED (oxygen was down to 86-87), FEELING ABNORMAL (brain fog), MEMORY IMPAIRMENT (keeps forgetting things), LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (this situation is impacting her daily life), ARTHRALGIA (joint pain/still has joint pain), HEADACHE (daily headache) and NAUSEA (felt really nauseous). In November 2021, INFLUENZA LIKE ILLNESS (flu like symptoms) and VACCINATION SITE PAIN (pain in the injection site.) had resolved. At the time of the report, URTICARIA (hives on neck/hives on upper back/hives on the neck/completely covered with hives/diagnosed her with chronic hives.), ARTHRALGIA (joint pain/still has joint pain) and HEADACHE (daily headache) had not resolved, PAIN (agonizing pain), SWELLING (swelling), PRESYNCOPE (almost fainted), GAIT DISTURBANCE (has trouble walking), PAIN IN EXTREMITY (feet are very painful), DYSPNOEA (woke up gasping for air/her breathing has not been the same/her breathing has not been the same), OXYGEN SATURATION DECREASED (oxygen was down to 86-87), FEELING ABNORMAL (brain fog), MEMORY IMPAIRMENT (keeps forgetting things) and LOSS OF PERSONAL INDEPENDENCE IN DAILY ACTIVITIES (this situation is impacting her daily life) outcome was unknown and NAUSEA (felt really nauseous) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In November 2021, Oxygen saturation decreased: decreased (Low) Decreased. oxygen was down to 86-87..     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   She received an IV with steroids and inhaler as treatment. Concomitant medication included Birth control. Description of Hydroxyzine was reported as Antihistamine. Reporter stated that Hives got jumbled and after 24 hours she was completely covered with hives.She went to the urgent care and received an injection.She stated that she progressively got worst and she needed an ambulance and was sent to the emergency room. The reporter stated her vitals were not great.  Her oxygen was level was down and again she was back in the emergency room. Hives covered her all the body and were worst at night.   This case was linked to MOD-2022-466775 (Patient Link).