arm started to rot; started "very very red", her arm started to rot. "very very red" and later the redness started to spread upwards.; red parts later started producing pus; Her arm continued to get worse and started swelling; She couldn't even sleep; Her arm continued to get worse/the redness started to spread upwards; injection that exploded with blood; the infection went down into the bone; the infection was so advanced that it went into her heart too , the infection went down into the bone; she can't work; She was scared thinking that they would have to cut off her arm.; hurt a lot, is in so much pain that she can't work; This spontaneous case was reported by a consumer and describes the occurrence of OSTEOMYELITIS (the infection went down into the bone), CARDIAC INFECTION (the infection was so advanced that it went into her heart too , the infection went down into the bone), LIMB DISCOMFORT (arm started to rot), ERYTHEMA (started "very very red",her arm started to rot."very very red" and later the redness started to spread upwards.), PUSTULE (red parts later started producing pus), PERIPHERAL SWELLING (Her arm continued to get worse and started swelling), INSOMNIA (She couldn't even sleep), CONDITION AGGRAVATED (Her arm continued to get worse/the redness started to spread upwards), INJECTION SITE HAEMORRHAGE (injection that exploded with blood) and FEAR (She was scared thinking that they would have to cut off her arm.) in a 56-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 053E21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.    On 23-Jul-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. In 2021, the patient experienced OSTEOMYELITIS (the infection went down into the bone) (seriousness criteria hospitalization and medically significant), CARDIAC INFECTION (the infection was so advanced that it went into her heart too , the infection went down into the bone) (seriousness criteria hospitalization and medically significant), PUSTULE (red parts later started producing pus) (seriousness criterion hospitalization), PERIPHERAL SWELLING (Her arm continued to get worse and started swelling) (seriousness criterion hospitalization), INSOMNIA (She couldn't even sleep) (seriousness criterion hospitalization), CONDITION AGGRAVATED (Her arm continued to get worse/the redness started to spread upwards) (seriousness criterion hospitalization), INJECTION SITE HAEMORRHAGE (injection that exploded with blood) (seriousness criterion hospitalization) and PAIN (hurt a lot, is in so much pain that she can't work). In August 2021, the patient experienced LIMB DISCOMFORT (arm started to rot) (seriousness criterion hospitalization) and ERYTHEMA (started "very very red", her arm started to rot. "very very red" and later the redness started to spread upwards.) (seriousness criterion hospitalization). On an unknown date, the patient experienced FEAR (She was scared thinking that they would have to cut off her arm.) (seriousness criterion medically significant) and IMPAIRED WORK ABILITY (she can't work). The patient was treated with Surgery (to remove part of her bone) for Osteomyelitis and Surgery (Catheter placement) for Cardiac infection. At the time of the report, OSTEOMYELITIS (the infection went down into the bone), CARDIAC INFECTION (the infection was so advanced that it went into her heart too , the infection went down into the bone), LIMB DISCOMFORT (arm started to rot), ERYTHEMA (started "very very red", her arm started to rot. "very very red" and later the redness started to spread upwards.), PUSTULE (red parts later started producing pus), PERIPHERAL SWELLING (Her arm continued to get worse and started swelling), INSOMNIA (She couldn't even sleep), CONDITION AGGRAVATED (Her arm continued to get worse/the redness started to spread upwards), INJECTION SITE HAEMORRHAGE (injection that exploded with blood), FEAR (She was scared thinking that they would have to cut off her arm.) and IMPAIRED WORK ABILITY (she can't work) outcome was unknown and PAIN (hurt a lot, is in so much pain that she can't work) had not resolved.        mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) dosing remained unchanged.       Caller stated that it almost killed her. 12 days after the injection, her arm started to rot. First, the doctors she consulted, gave her pills that did nothing for her. She was admitted and had to undergo surgery. They tried to remove as much of the infection as possible. She said that the infection went down into the bone, and she was unsure but thought they had to remove part of her bone. She was scared thinking that they would have to cut off her arm. The doctors told her that the infection was so advanced that it went into her heart too, so they had to insert a catheter. Caller said that she was still on antibiotics. Patient went to a clinic where HCP administered an injection that exploded with blood. Treatment medication include Pills, injection, surgery, antibiotics with unknown indication. No concomitant medication was reported.  Company Comment: This case concerns  a 56-year-old female patient with no previous relevant medical history reported, who experienced the serious unexpected events of Osteomyelitis, Infection, Cardiac infection, Limb discomfort, Erythema, Pustule, Peripheral swelling, Insomnia, Injection site haemorrhage, Fear, Pain and Impaired work ability. The events occurred (onset dates not reported) on the days following the first  dose of COVID-19 Vaccine Moderna (mRNA-1273). Diagnostic workups and treatment details were not provided. The benefit-risk relationship of COVID-19 Vaccine Moderna (mRNA-1273) is not affected by this report.   This case was linked to MOD-2021-435718 (Patient Link).; Sender's Comments: This case concerns  a 56-year-old female patient with no previous relevant medical history reported, who experienced the serious unexpected events of Osteomyelitis, Infection, Cardiac infection, Limb discomfort, Erythema, Pustule, Peripheral swelling, Insomnia, Injection site haemorrhage, Fear, Pain and Impaired work ability. The events occurred (onset dates not reported) on the days following the first  dose of COVID-19 Vaccine Moderna (mRNA-1273). Diagnostic workups and treatment details were not provided. The benefit-risk relationship of COVID-19 Vaccine Moderna (mRNA-1273) is not affected by this report.