blood oxygen dropped to 50% and oxygen levels are now at 70%; difficulty breathing/could not breathe right; fluid in their lungs; fluid around their heart; Congenital heart failure; feared/scared; got both doses of the Moderna vaccine on the left arm and also both doses of the Pfizer vaccine on the opposite arm; Moderna first dose was administered on 7 or 17 Jan2021, lot#025L20A (expiry date 25Jun2021), and the second on 25Feb2021; Congenital heart failure; This spontaneous case was reported by a consumer and describes the occurrence of HYPOXIA (blood oxygen dropped to 50% and oxygen levels are now at 70%), DYSPNOEA (difficulty breathing/could not breathe right), PULMONARY OEDEMA (fluid in their lungs), PERICARDIAL EFFUSION (fluid around their heart), HEART DISEASE CONGENITAL (Congenital heart failure) and CARDIAC FAILURE (Congenital heart failure) in a 73-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 001A21A and 025L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.    Co-suspect product included non-company product TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for COVID-19 vaccination.    Concomitant products included ATORVASTATIN, ACETYLSALICYLIC ACID (ASPIRIN 81), APIXABAN, AMLODIPINE BESYLATE, CARVEDILOL, LOSARTAN, FUROSEMIDE, POTASSIUM CHLORIDE and MAGNESIUM OXIDE for an unknown indication.   On 01-Feb-2021, the patient received first dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) 1 dosage form. On 22-Feb-2021, received second dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) dosage was changed to 1 dosage form. On 25-Feb-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 received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In 2021, the patient experienced HYPOXIA (blood oxygen dropped to 50% and oxygen levels are now at 70%) (seriousness criteria hospitalization and medically significant) and DYSPNOEA (difficulty breathing/could not breathe right) (seriousness criterion hospitalization). On an unknown date, the patient experienced PULMONARY OEDEMA (fluid in their lungs) (seriousness criterion medically significant), PERICARDIAL EFFUSION (fluid around their heart) (seriousness criterion medically significant), HEART DISEASE CONGENITAL (Congenital heart failure) (seriousness criterion medically significant), FEAR (feared/scared), COVID-19 IMMUNISATION (got both doses of the Moderna vaccine on the left arm and also both doses of the Pfizer vaccine on the opposite arm), INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Moderna first dose was administered on 7 or 17 Jan2021, lot#025L20A (expiry date 25Jun2021), and the second on 25Feb2021) and CARDIAC FAILURE (Congenital heart failure) (seriousness criterion medically significant). The patient was hospitalized for 5 days due to DYSPNOEA and HYPOXIA. At the time of the report, HYPOXIA (blood oxygen dropped to 50% and oxygen levels are now at 70%) and DYSPNOEA (difficulty breathing/could not breathe right) had not resolved, PULMONARY OEDEMA (fluid in their lungs), PERICARDIAL EFFUSION (fluid around their heart), HEART DISEASE CONGENITAL (Congenital heart failure), FEAR (feared/scared), COVID-19 IMMUNISATION (got both doses of the Moderna vaccine on the left arm and also both doses of the Pfizer vaccine on the opposite arm) and CARDIAC FAILURE (Congenital heart failure) outcome was unknown and INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Moderna first dose was administered on 7 or 17 Jan2021, lot#025L20A (expiry date 25Jun2021), and the second on 25Feb2021) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In 2021, Oxygen saturation: 50% (Low) blood oxygen dropped to 50%. and 70% (Low) oxygen levels are now at 70%.         HCP told the patient they have too much antibodies on their system. Patient had labs done last Monday and was still waiting on the results. Patient was  on oxygen . HCP was treating the Patient for Congenital heart failure.  Company Comment: This is a case of inappropriate schedule of vaccine administered and covid 19 immunisation (revaccination with different covid 19 vaccine) with associated adverse events of hypoxia, dyspnoea, pulmonary oedema, pericardial effusion, heart disease congenital and cardiac failure. 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.  Further information is expected.; Sender's Comments: This is a case of inappropriate schedule of vaccine administered and covid 19 immunisation (revaccination with different covid 19 vaccine) with associated adverse events of hypoxia, dyspnoea, pulmonary oedema, pericardial effusion, heart disease congenital and cardiac failure. 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.  Further information is expected.