shortness of breath/Difficulty breathing; fever of 100.8 degrees F; malaise; Hypoxic; This spontaneous case was reported by a nurse and describes the occurrence of DYSPNOEA (shortness of breath/Difficulty breathing), PYREXIA (fever of 100.8 degrees F), MALAISE (malaise) and HYPOXIA (Hypoxic) in a 58-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 047A21A, 014C21A and D59H21A) for COVID-19 vaccination.     The patient's past medical history included Breast cancer female (Left Breast Cancer. They did a mastectomy and chemo therapy.) in September 2008 and Atrial fibrillation (Rapid atrial fibrillation.This caused many issues including her being diagnosed with Sick Sinus Syndrome where they added a dual chamber pacemaker in. In 2010 they did a Maze procedure which included a left atrial appendage atriotomy.) in March 2009. Concurrent medical conditions included Overweight. Concomitant products included CARVEDILOL, LISINOPRIL, ACETYLSALICYLIC ACID (BABY ASPIRIN), ROSUVASTATIN, CALCIUM CARBONATE, COLECALCIFEROL (VITAMIN D 2000), FUROSEMIDE (LASIX [FUROSEMIDE]), OMEGA-3-ACID ETHYL ESTER (LOVAZA), POTASSIUM, NAPROXEN, ZOLPIDEM TARTRATE (AMBIEN CR), DIPHENHYDRAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE HYDROCHLORIDE]), OXYCODONE HYDROCHLORIDE, OXYCODONE TEREPHTHALATE, PARACETAMOL (PERCOCET [OXYCODONE HYDROCHLORIDE;OXYCODONE TEREPHTHALATE;PARACETAMOL]), ACETYLSALICYLIC ACID (ASPIRIN (E.C.)), FLUTICASONE, MAGNESIUM, DOCUSATE SODIUM, SENNA ALEXANDRINA (SENOKOT-S), ZINC and VITAMIN C [ASCORBIC ACID] for an unknown indication.   On 26-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 29-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 02-Jan-2022, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 27-Jan-2022, the patient experienced HYPOXIA (Hypoxic) (seriousness criterion medically significant). On 05-Feb-2022, the patient experienced DYSPNOEA (shortness of breath/Difficulty breathing) (seriousness criterion hospitalization). On 20-Feb-2022, the patient experienced PYREXIA (fever of 100.8 degrees F) (seriousness criterion hospitalization) and MALAISE (malaise) (seriousness criterion hospitalization). The patient was hospitalized from 05-Feb-2022 to 10-Feb-2022 due to DYSPNOEA, then from 20-Feb-2022 to 23-Feb-2022 due to MALAISE and PYREXIA. The patient was treated with OXYGEN at an unspecified dose and frequency; AZITHROMYCIN at an unspecified dose and frequency; CEFACLOR (VERCEF [CEFACLOR]) at an unspecified dose and frequency; DEXAMETHASONE (DECADRON [DEXAMETHASONE]) at an unspecified dose and frequency and METHYLPREDNISOLONE SODIUM SUCCINATE (SOLUMEDROL) at an unspecified dose and frequency. On 30-Jan-2022, HYPOXIA (Hypoxic) had resolved. At the time of the report, DYSPNOEA (shortness of breath/Difficulty breathing), PYREXIA (fever of 100.8 degrees F) and MALAISE (malaise) was resolving.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 27-Jan-2022, Oxygen saturation: 80s (Low) In the 80s. On 05-Feb-2022, Oxygen saturation: 70s (Low) in the 70s.. On 05-Feb-2022, White blood cell count: 29.7 (abnormal) 29.7. In February 2022, Culture: nothing grew (normal) nothing grew. In February 2022, Echocardiogram: myocarditis or pericarditis not seen myocarditis or pericarditis not seen. She usually had weird symptoms normally but they did not see anything new. In February 2022, Laboratory test: negative (Negative) Negative. In February 2022, SARS-CoV-2 test: negative (Negative) Negative. In February 2022, White blood cell count: 27.9 (abnormal) 27.9.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   On 27-Jan-2022, the patient became hypoxic. She had oxygen at home (for her comorbidities) so she was able to use that. It was controllable at home. Her oxygen saturation (SpO2) was in the 80s, but she was able to get them to the 90s. This was resolved by Sunday. On 05-Feb-2022, she woke up in the middle of the night having difficulty breathing. She could not make it through the day. Her SpO2 was in the 70s even on 3L of oxygen. So, she was hospitalized on that day. She had a white blood cell count of 27.9. Her COVID test and other labs came back negative. They did an echocardiogram and did not see myocarditis or pericarditis. She usually had weird symptoms normally, but they did not see anything new. While in the hospital, she was given 6L of oxygen, Azithromycin IV, then 4 days Azithromycin oral every day. She was also given Vercef IV every day for 5 days then oral for 2.5 days. She was also put on steroids including Decadron 6mg every day for 2 days. Decadron was stopped and solumedrol IV was started for 4 doses. Patient was put on a taper pack-40 mg for 3 days, 30 mg for 3 days, 20 mg for 3 days and then 10 mg. Her first hospitalization was till 10-Feb-2022. Before she could finish the taper pack she was hospitalized again. On 20-Feb-2022, she woke up and within an hour and a half she noticed a fever of 100.8 degrees F with some malaise. She went back to the hospital that day. They gave patient Azithromycin 1 day IV then 1 day oral and Vercef for 3 days. Her cultures on both hospital visits showed nothing grew so they stopped the antibiotics. She had a white blood cell count of 29.7 during second hospitalization. Also, her COVID test and other labs came back negative again. She had the typical COVID pneumonia appearance but no COVID. Since the second hospitalization, oxygen was given a couple of times. It was not resolved. She was slowly improving. Her second hospitalization was till 23-Feb-2022. Multivitamin was reported as one of the concomitants. Company comment : This Spontaneous case concerns a 58-year-old, female patient with medical history of Obesity (body mass index 40.6), oxygen user and atrial fibrillation, who experienced the unexpected, serious (Hospitalization) events of dyspnoea, pyrexia, malaise and Hypoxia (Medically significant). The patient became hypoxic 25 days after receiving the third dose of mRNA-1273. 9 days after, she woke up in the middle of the night with dyspnoea and her SpO2 was in the 70s even on 3L of oxygen, hence she was hospitalized for 5 days and received oxygen, azithromycin, cefaclor and steroids. Her white blood cell count was 27.9 (no units were reported) along with COVID test and other laboratory tests not specified that came back negative, including an echocardiogram that was negative for myocarditis or pericarditis. 5 days after discharge, she was hospitalized again with pyrexia and malaise. She received azithromycin and cefaclor. Her cultures on both hospital visits were negative, so antibiotics were stopped. Her white blood cell count was 29.7 (no units were reported), COVID-19 test was negative. It was reported that she had "the typical COVID pneumonia appearance" but COVID-19 was not confirmed. The medical history of Obesity (body mass index 40.6), oxygen user and atrial fibrillation and patient's polypharmacy remain as confounders. The benefit-risk relationship of the mRNA-1273 is not affected by this report.; Sender's Comments: This Spontaneous case concerns a 58-year-old, female patient with medical history of Obesity (body mass index 40.6), oxygen user and atrial fibrillation, who experienced the unexpected, serious (Hospitalization) events of dyspnoea, pyrexia, malaise and Hypoxia (Medically significant). The patient became hypoxic 25 days after receiving the third dose of mRNA-1273. 9 days after, she woke up in the middle of the night with dyspnoea and her SpO2 was in the 70s even on 3L of oxygen, hence she was hospitalized for 5 days and received oxygen, azithromycin, cefaclor and steroids. Her white blood cell count was 27.9 (no units were reported) along with COVID test and other laboratory tests not specified that came back negative, including an echocardiogram that was negative for myocarditis or pericarditis. 5 days after discharge, she was hospitalized again with pyrexia and malaise. She received azithromycin and cefaclor. Her cultures on both hospital visits were negative, so antibiotics were stopped. Her white blood cell count was 29.7 (no units were reported), COVID-19 test was negative. It was reported that she had "the typical COVID pneumonia appearance" but COVID-19 was not confirmed. The medical history of Obesity (body mass index 40.6), oxygen user and atrial fibrillation and patient's polypharmacy remain as confounders. The benefit-risk relationship of the mRNA-1273 is not affected by this report.