he started to have some breathing problems; he had a heart problem; SIBO test (a 10 tube breath test over 15 minutes), which led the doctors to believe that he might have had a bacterial infection in the stomach; Within 10 days, he had pains in his stomach; The major problem is bloating in his stomach/ like a balloon in his stomach; This spontaneous case was reported by a patient and describes the occurrence of DYSPNOEA (he started to have some breathing problems), ABDOMINAL PAIN UPPER (Within 10 days, he had pains in his stomach), ABDOMINAL DISTENSION (The major problem is bloating in his stomach/ like a balloon in his stomach), CARDIAC DISORDER (he had a heart problem) and BACTERIAL INFECTION (SIBO test (a 10 tube breath test over 15 minutes), which led the doctors to believe that he might have had a bacterial infection in the stomach) in an 80-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis.     It was reported that patient has no allergies and no medical history.    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) (Intramuscular) dosage was changed to 1 dosage form. In March 2021, the patient experienced ABDOMINAL PAIN UPPER (Within 10 days, he had pains in his stomach) and ABDOMINAL DISTENSION (The major problem is bloating in his stomach/ like a balloon in his stomach). On an unknown date, the patient experienced DYSPNOEA (he started to have some breathing problems), CARDIAC DISORDER (he had a heart problem) and BACTERIAL INFECTION (SIBO test (a 10 tube breath test over 15 minutes), which led the doctors to believe that he might have had a bacterial infection in the stomach). The patient was treated with SACUBITRIL, VALSARTAN (ENTRESTO) for Ejection fraction abnormal, at an unspecified dose and frequency and RIFAXIMIN (XIFAXAN) for Bacterial infection, at a dose of 550 milligram. At the time of the report, DYSPNOEA (he started to have some breathing problems), ABDOMINAL PAIN UPPER (Within 10 days, he had pains in his stomach), ABDOMINAL DISTENSION (The major problem is bloating in his stomach/ like a balloon in his stomach), CARDIAC DISORDER (he had a heart problem) and BACTERIAL INFECTION (SIBO test (a 10 tube breath test over 15 minutes), which led the doctors to believe that he might have had a bacterial infection in the stomach) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In March 2021, Computerised tomogram: they couldn't see anything.. On an unknown date, Ejection fraction: his ejection fraction is only 25..     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   No concomitant medications were reported. Patient did not receive any other vaccine in the 4 weeks prior to COVID-19 vaccine. Patient took Pfizer first booster dose on unknown date. On 13-Sep-2022 patient took Pfizer second booster (lot numbers was unknown). After second Moderna almost 2 years now, he started to have breathing problems. The major problem was bloating in his stomach. As months went on, it's gotten bigger and bigger. It got worse and worse. His local gastroenterologist didn't know what to do, so that is why he was calling. He's seen several gastro doctors. He's been going off and on to doctors. The Patient got pacemaker several months later 10-Aug-2022. His stomach constantly got worse and worse. Doctors don't know what it was. It was like a balloon (basketball) in front of his stomach. The events occurred about 10-15 days after his second dose. The patient had as SIBO (Small intestinal bacterial overgrowth) test which was a 10-tube test over 15 minutes that led the doctors to believe that he might have bacterial infection in the stomach. He subsequently took Xifaxan 550 mg, The patient reported that it didn't do anything.