Blood pressure bottomed out/ It went way low; Heart failure; This spontaneous case was reported by a patient and describes the occurrence of CARDIAC FAILURE (Heart failure) and HYPOTENSION (Blood pressure bottomed out/ It went way low) in a 75-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 048LZ1A, 939901, 003B21A and 025A21A) for COVID-19 prophylaxis.  The patient never had COVID positive test or diagnosis. Other vaccines given within 1 month prior to Moderna COVID-19 vaccine was reported as none. The patient's past medical history included Hives (Skelaxin (hives)). Concurrent medical conditions included Drug allergy (Reglan), Drug allergy (Compazine (phenothiazines)), Drug allergy (Mellaril (phenothiazines)), Sulfonamide allergy (Sulfa), Drug allergy (Codeine), Drug allergy (Flexeril), Drug allergy (Flagyl), Drug allergy (Hydrocodone), Drug allergy (Oxycodone), Drug allergy (Skelaxin (hives)), Drug allergy (Dilaudid), Drug allergy (Imitrex) and Sensitisation. Concomitant products included INFLUENZA VACCINE (FLU SYRINGE) for an unknown indication.  On 27-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 27-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 22-Oct-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 03-Apr-2022, received fourth dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In April 2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced HYPOTENSION (Blood pressure bottomed out/ It went way low) (seriousness criterion hospitalization). In 2022, the patient experienced CARDIAC FAILURE (Heart failure) (seriousness criteria hospitalization and medically significant). The patient was hospitalized for 7 days due to CARDIAC FAILURE and HYPOTENSION. In 2022, CARDIAC FAILURE (Heart failure) and HYPOTENSION (Blood pressure bottomed out/ It went way low) had resolved.  DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In April 2022, Blood pressure measurement: Blood pressure bottomed out. It went way low. In 2022, Cardiac function test: Heart function did not return to normal until recently. It took a long time for heart to return to normal.  For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered CARDIAC FAILURE (Heart failure) and HYPOTENSION (Blood pressure bottomed out/ It went way low) to be related.  The patient had heart failure and blood pressure was way low. It was a serious reaction. It was assumed that it had to be from the booster because there was no other explanation. Patient would be needing (was recommended) another booster. However, patient would not be taking another mRNA vaccine and asked if it would be safe to take one of the vaccines being developed that was not an mRNA vaccine. The patient had a question about ingredients in the vaccine. The patient gets the flu shot every year but never had a reaction. Patient's healthcare providers assumed that something in the mRNA vaccines was different enough that was causing a response in patient's body and did not think that the disease itself can cause anaphylaxis, so it had to be the vaccine. Their theory was that it would be safe to take a non-mRNA vaccine.  Company comment: This spontaneous case concerns a 75-year-old female patient, with relevant medical history of drug hypersensitivity, who experienced the unexpected serious (medically significant and hospitalization) AESI of Cardiac failure and unexpected serious (medically significant) event of Hypotension after receiving the mRNA-1273 vaccine as 4th dose. Hypotension occurred 12 hours post vaccination. Patient was hospitalized for a week due to heart failure. Clinical course and treatment details were not reported. The outcome of cardiac failure was reported as resolved. Patient received 2-dose primary series of mRNA-1273 vaccine 28 days apart. Approximately 7 months later, patient received 3rd dose of mRNA-1273 vaccine. The current 4th dose mRNA-1273 vaccine was administered approximately 5 months after the 3rd dose. The benefit-risk relationship of mRNA-1273 is not affected by this report. Events assessed serious based on medical judgement.  This case was linked to MOD-2022-654193, MOD-2022-654184 (Patient Link).; Sender's Comments: This spontaneous case concerns a 75-year-old female patient, with relevant medical history of drug hypersensitivity, who experienced the unexpected serious (medically significant and hospitalization) AESI of Cardiac failure and unexpected serious (medically significant) event of Hypotension after receiving the mRNA-1273 vaccine as 4th dose. Hypotension occurred 12 hours post vaccination. Patient was hospitalized for a week due to heart failure. Clinical course and treatment details were not reported. The outcome of cardiac failure was reported as resolved. Patient received 2-dose primary series of mRNA-1273 vaccine 28 days apart. Approximately 7 months later, patient received 3rd dose of mRNA-1273 vaccine. The current 4th dose mRNA-1273 vaccine was administered approximately 5 months after the 3rd dose. The benefit-risk relationship of mRNA-1273 is not affected by this report. Events assessed serious based on medical judgement.