diarrhea; fatigue; chills; pain and redness near the injection site; pain and redness near the injection site; fever; muscle aches; hypothermia; This spontaneous case was reported by a patient and describes the occurrence of HYPOTHERMIA (hypothermia) in a 75-year-old female patient who received mRNA-1273.815 (SPIKEVAX 2023-2024) (batch no. ASKU) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     Previously administered products included for Product used for unknown indication: Flu shot (at the beginning of October) in October 2023, Prevnar(Pneumonia) 20 (a few days later) in October 2023, Multivitamin, Vitamin D, Vitamin B 100 complex, iron Eurofer, Synthroid and levothyroxine (0.088). Past adverse reactions to the above products included No adverse event with Flu shot, Multivitamin, Prevnar(Pneumonia) 20, Synthroid, Vitamin B 100 complex, Vitamin D, iron Eurofer and levothyroxine. Concurrent medical conditions included Hypothyroidism, Osteoporosis, Allergy to antibiotic (Macrolide) and Penicillin allergy (Possibly penicillin).    On 14-Oct-2023, the patient received dose of mRNA-1273.815 (SPIKEVAX 2023-2024) (unknown route) 1 dosage form. On 14-Oct-2023, the patient experienced DIARRHOEA (diarrhea), FATIGUE (fatigue), CHILLS (chills), VACCINATION SITE PAIN (pain and redness near the injection site), VACCINATION SITE ERYTHEMA (pain and redness near the injection site), PYREXIA (fever) and MYALGIA (muscle aches). In October 2023, the patient experienced HYPOTHERMIA (hypothermia) (seriousness criterion medically significant). At the time of the report, HYPOTHERMIA (hypothermia) outcome was unknown and DIARRHOEA (diarrhea), FATIGUE (fatigue), CHILLS (chills), VACCINATION SITE PAIN (pain and redness near the injection site), VACCINATION SITE ERYTHEMA (pain and redness near the injection site), PYREXIA (fever) and MYALGIA (muscle aches) had not resolved.        For mRNA-1273.815 (SPIKEVAX 2023-2024) (Unknown), the reporter did not provide any causality assessments.   No concomitant medication was reported.  Patient experienced various side effects the next few days. A lot of side effects. But now it was 3 weeks after the shot and they were till suffering for overwhelming fatigue. Patient had 4 Pfizer and 2 Moderna. Got the vaccine Toronto. She was in bed and cannot access vaccines records at this time.  No treatment information was reported. Company comment This spontaneous case concerns a patient of a 75-year-old female patient with relevant medical history of Hypothyroidism, who experienced the unexpected, serious (medically significant), event of hypothermia, which occurred on the same month that a dose of mRNA-1273.815 (SPIKEVAX 2023-2024) was administered. It was reported that 3 weeks after the shot she was still suffering from overwhelming fatigue. She had chills, pain and redness near the injection site. Sometimes she had a fever and sometimes very very low temperature like hypothermia, muscle aches, diarrhea. She had 4 Pfizer and 2 Moderna COVID-19 vaccine. No further clinical information was provided for review. The medical history of Hypothyroidism could be a contributory factor for hypothermia and the non-serious events of fatigue and myalgia. The benefit-risk relationship of mRNA-1273.815 (SPIKEVAX 2023-2024) vaccine is not affected by this report.