Flu again after second vaccine dose; Pulse oxygen level dropped to 75 after second vaccine dose; Hard time breathing after second vaccine dose; Lungs had fluid after second vaccine dose; Horrible mouth sores after second vaccine dose; Very weak after second vaccine dose/No energy after second vaccine dose; Patient feels like he was hit by a big truck; Trouble sleeping at night; This spontaneous case was reported by a patient (subsequently medically confirmed) and describes the occurrence of INFLUENZA (Flu again after second vaccine dose), HEART RATE DECREASED (Pulse oxygen level dropped to 75 after second vaccine dose), DYSPNOEA (Hard time breathing after second vaccine dose), PULMONARY OEDEMA (Lungs had fluid after second vaccine dose), STOMATITIS (Horrible mouth sores after second vaccine dose) and ASTHENIA (Very weak after second vaccine dose/No energy after second vaccine dose) in an 80-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 011A21A and 007M20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included No adverse event (No medical history was provided.).   In January 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 27-Feb-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 INFLUENZA (Flu again after second vaccine dose) (seriousness criterion hospitalization), HEART RATE DECREASED (Pulse oxygen level dropped to 75 after second vaccine dose) (seriousness criterion hospitalization), DYSPNOEA (Hard time breathing after second vaccine dose) (seriousness criterion hospitalization), PULMONARY OEDEMA (Lungs had fluid after second vaccine dose) (seriousness criteria hospitalization and medically significant), STOMATITIS (Horrible mouth sores after second vaccine dose) (seriousness criterion hospitalization), ASTHENIA (Very weak after second vaccine dose/No energy after second vaccine dose) (seriousness criterion hospitalization) and INSOMNIA (Trouble sleeping at night). On an unknown date, the patient experienced FEELING ABNORMAL (Patient feels like he was hit by a big truck). The patient was hospitalized from 13-Mar-2021 to 16-Mar-2021 due to ASTHENIA, DYSPNOEA, HEART RATE DECREASED, INFLUENZA, PULMONARY OEDEMA and STOMATITIS. At the time of the report, INFLUENZA (Flu again after second vaccine dose), HEART RATE DECREASED (Pulse oxygen level dropped to 75 after second vaccine dose), DYSPNOEA (Hard time breathing after second vaccine dose), PULMONARY OEDEMA (Lungs had fluid after second vaccine dose) and STOMATITIS (Horrible mouth sores after second vaccine dose) had resolved, ASTHENIA (Very weak after second vaccine dose/No energy after second vaccine dose) and FEELING ABNORMAL (Patient feels like he was hit by a big truck) outcome was unknown and INSOMNIA (Trouble sleeping at night) had not resolved. Not Provided    DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Echocardiogram: normal (normal) normal.         No concomitant medications were provided. Treatment medications included anti-herpes and mouth wash for mouth sores. Action taken with mRNA-1273 in response to the events was not Applicable.  Based on the information provided which includes a strong temporal association between the use of mRNA-1273 vaccine and onset of the reported events, excluding other etiologies causal relationship cannot be excluded.   This case was linked to MODERNATX, INC.-MOD-2021-078124 (E2B Linked Report).; Sender's Comments: Based on the information provided which includes a strong temporal association between the use of mRNA-1273 vaccine and onset of the reported events, excluding other etiologies causal relationship cannot be excluded. MODERNATX, INC.-MOD-2021-078124:Case for patient 1