hypoxic/my oxygen level dropped; pleuritic pain; This spontaneous case was reported by a consumer and describes the occurrence of HYPOXIA (hypoxic/my oxygen level dropped) in a 69-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 031L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Sleep apnea in April 2019. Concurrent medical conditions included Pulmonary hypertension since June 2019, Pulmonary arterial hypertension since 05-Mar-2021, Heart failure since 05-Mar-2021, Respiratory failure since 05-Mar-2021 and Cardiomegaly since 05-Mar-2021. Concomitant products included VITAMIN D3 for Vitamin deficiency, VITAMIN B COMPLEX (B COMPLEX [VITAMIN B COMPLEX]) for an unknown indication.    On 05-Feb-2021 at 10:30 AM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, the patient experienced HYPOXIA (hypoxic/my oxygen level dropped) (seriousness criterion medically significant) and PLEURITIC PAIN (pleuritic pain). At the time of the report, HYPOXIA (hypoxic/my oxygen level dropped) had resolved and PLEURITIC PAIN (pleuritic pain) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 23-Feb-2021, Echocardiogram: abnormal (abnormal) pulmonary artery systolic pressure was around 44.     The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   For mRNA-1273 (Moderna COVID-19 Vaccine) (unknown), the reporter did not provide any causality assessments. The initial sign of a problem was about 2 hours after the first vaccine while Patient seated at desk at home. Patient was hit by a sharp pain in the right rib area below where she had just received the vaccine. It was pleuritic pain, making it difficult to breathe and to speak. Patient was taken to the emergency room, where had a chest X-ray, a CT scan and labs. Patient mentioned the vaccine to the staff, but none of them had heard of any reaction like that and dismissed concern. The next day at home, patient oxygen level dropped and had to use daytime supplemental oxygen for the next 3 weeks. Patient had used oxygen at night with CPAP machine but not during the day. Patient used the oxygen for the next 3 weeks and then was able to stop using it the fourth week after the vaccine. Patient was relieved but afraid to take the second vaccine at the end of that week. Patient called the company, Moderna, as well as my pulmonologist's nurse practitioner, but everyone encouraged her to take the second dose, because there was no similar reaction reported by the CDC.  Company comment: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  Patient has SLEEP APNEA, PULMONARY HYPERTENSION and HEART FAILURE which can confound the event. Unlikely, that the event are related to the vaccine.   This case was linked to MOD-2021-029767, MOD-2021-029767 (Patient Link).; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  Patient has SLEEP APNEA, PULMONARY HYPERTENSION and HEART FAILURE which can confound the event. Unlikely, that the event are related to the vaccine.