This spontaneous case was reported by a patient and describes the occurrence of GASTROINTESTINAL INFECTION (stomach infection) in a 71-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The patient's past medical history included Drug resistance. Concurrent medical conditions included Immunosuppression. In August 2021, the patient received dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced GASTROINTESTINAL INFECTION (stomach infection) (seriousness criterion hospitalization). At the time of the report, GASTROINTESTINAL INFECTION (stomach infection) outcome was unknown. This case was identified as part of a retrospective clean-up activity where certain emails received in the Moderna mailbox were missed to be booked-in. No concomitant medications were reported. No treatment medications were reported. Patient was a small business owner received booster vaccine and spent 14 weeks in the hospital. Patient was reminding that another booster was mid of December. Patient will be hospitalized again soon for surgery. Company comment: This spontaneous case concerns a 71-year-old patient of unknown gender with concurrent conditions of drug-resistance and immunocompromised status, who experienced an unexpected, serious event of Gastrointestinal infection in association with a booster dose of mRNA-1273 vaccine that led to hospitalization. Exact onset latency of the event relative to vaccination cannot be determined with unknown event's onset date and vaccination date. Reportedly, patient has stayed in the hospital for 14 weeks due to stomach infection. Patient also reported of a planned hospitalization for an unspecified surgery. Patient received all mRNA-1273 vaccine on unknown dates. Further details on the medical history, vaccination history, clinical course, diagnostics, and treatments were not reported. Patient's immunocompromised and drug-resistance status are strong predisposing risk factors to various infections. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement. This case was linked to MOD-2021-259957 (Patient Link). Sender's Comments: This spontaneous case concerns a 71-year-old patient of unknown gender with concurrent conditions of drug-resistance and immunocompromised status, who experienced an unexpected, serious event of Gastrointestinal infection in association with a booster dose of mRNA-1273 vaccine that led to hospitalization. Exact onset latency of the event relative to vaccination cannot be determined with unknown event's onset date and vaccination date. Reportedly, patient has stayed in the hospital for 14 weeks due to stomach infection. Patient also reported of a planned hospitalization for an unspecified surgery. Patient received all mRNA-1273 vaccine on unknown dates. Further details on the medical history, vaccination history, clinical course, diagnostics, and treatments were not reported. Patient's immunocompromised and drug-resistance status are strong predisposing risk factors to various infections. The benefit-risk relationship of mRNA-1273 is not affected by this report. Event's seriousness assessed based on medical judgement.