severe pulmonary arterial hypertension; my oxygen level dropped; pleuritic pain; making it difficult to  breath; This spontaneous case was reported by a consumer and describes the occurrence of PULMONARY HYPERTENSION (severe pulmonary arterial hypertension), HYPOXIA (my oxygen level dropped), PLEURITIC PAIN (pleuritic pain) and DYSPNOEA (making it difficult to  breath) in a 69-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 026A21A and 031L20A) for COVID-19 vaccination.     The patient's past medical history included Sleep apnea (mild) in April 2019. Concurrent medical conditions included Pulmonary arterial hypertension (Severe, possible mild PH) since June 2019. Concomitant products included VITAMIN D3 for Deficiency vitamin, VITAMIN B COMPLEX (B COMPLEX [VITAMIN B COMPLEX]) for an unknown indication.   On 05-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 05-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced PULMONARY HYPERTENSION (severe pulmonary arterial hypertension) (seriousness criteria hospitalization and medically significant), HYPOXIA (my oxygen level dropped) (seriousness criteria hospitalization and medically significant), PLEURITIC PAIN (pleuritic pain) (seriousness criterion hospitalization) and DYSPNOEA (making it difficult to  breath) (seriousness criterion hospitalization). The patient was hospitalized from 14-Jun-2021 to 03-Jul-2021 due to DYSPNOEA, HYPOXIA, PLEURITIC PAIN and PULMONARY HYPERTENSION. At the time of the report, PULMONARY HYPERTENSION (severe pulmonary arterial hypertension), HYPOXIA (my oxygen level dropped), PLEURITIC PAIN (pleuritic pain) and DYSPNOEA (making it difficult to  breath) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 23-Feb-2021, Echocardiogram: 44 (Inconclusive) showed my pulmonary artery's systolic pressure was around 44.. On an unknown date, Brain natriuretic peptide: elevated (High) indicating heart failure. On an unknown date, Echocardiogram: 110 (Inconclusive) systolic pressure of over 110 in the pulmonary artery.         For mRNA-1273 (Moderna COVID-19 Vaccine) (unknown), the reporter did not provide any causality assessments.  The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) was not applicable.  No treatment medications were reported  The patient was now homebound, having been diagnosed since the second dose 05-Mar-2021 with severe pulmonary arterial hypertension, heart cardiomegaly, heart failure and respiratory failure and was on 4 liters of oxygen seated and 8 liters of oxygen standing and walking in home and several medications.  initial sign of problem was about 2 hours after first vaccine while seated at desk at home and was hit by a sharp pain in the right rib area below where just received vaccine. It was pleuritic pain, making it difficult to breathe and to speak. I was taken to the emergency room, where had a chest X-ray, a CT scan and labs and was released with no treatment.  The next day oxygen level drop and had to use daytime supplemental oxygen for the next 3 weeks and used oxygen at night with CPAP machine but not during day. Used oxygen for next 3 weeks then was able to stop using it fourth week after vaccine. Was relieved but afraid to take second vaccine.  Patient had a repeat echocardiogram that showed my pulmonary artery systolic pressure was around 44. That was up from a previous echo, and nurse practitioner said they were still not certain that patient had progressive pulmonary hypertension, because heart looked fine.  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.   This case was linked to MOD-2021-029767, MOD-2021-029767, MOD-2021-272283 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 06-Jul-2021: Follow up information was received from initial reporter and contains no new information On 29-Jul-2021: Follow up received included: updated patient information, medical history, lab data. updated product information and concomitant products, added events and updated case seriousness, updated events outcome; 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.