inside of he left arm there is some redness that is travelling down arm; must be allergic to something (in booster)/made her afraid; full of fever; really bad side effects; COVID Arm; could "hardly get out of the bed"/sicker than a dog; down to almost elbow was red as a beet; left arm from shoulder blade down to almost elbow was very swollen; left arm from shoulder blade down to almost elbow was hard; This case was received via an unknown source (no reference has been entered for a health authority or license partner) on 20-Dec-2021 and was forwarded to Moderna on 20-Dec-2021.    This spontaneous case was reported by a consumer and describes the occurrence of VACCINATION COMPLICATION (really bad side effects), VACCINATION SITE REACTION (COVID Arm), ILLNESS (could "hardly get out of the bed"/sicker than a dog), ERYTHEMA (down to almost elbow was red as a beet) and PERIPHERAL SWELLING (left arm from shoulder blade down to almost elbow was very swollen) in a 76-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 067F21A, 015M20A and 030A21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On 09-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 09-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 15-Dec-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 16-Dec-2021, the patient experienced VACCINATION COMPLICATION (really bad side effects), VACCINATION SITE REACTION (COVID Arm), ILLNESS (could "hardly get out of the bed"/sicker than a dog), ERYTHEMA (down to almost elbow was red as a beet), PERIPHERAL SWELLING (left arm from shoulder blade down to almost elbow was very swollen), INDURATION (left arm from shoulder blade down to almost elbow was hard), ALLERGY TO VACCINE (must be allergic to something (in booster)/made her afraid) and PYREXIA (full of fever). On 20-Dec-2021, the patient experienced ERYTHEMA (inside of he left arm there is some redness that is travelling down arm). The patient was treated with DIPHENHYDRAMINE, PARACETAMOL, PHENYLPROPANOLAMINE HYDROCHLORIDE (BENADRYL [DIPHENHYDRAMINE;PARACETAMOL;PHENYLPROPANOLAMINE HYDROCHLORIDE]) (oral) in December 2021 for Vaccination site reaction, at a dose of UNK, q4h and DIPHENHYDRAMINE HYDROCHLORIDE, ZINC ACETATE (BENADRYL READYMIST ITCH STOPPING) (topical) in December 2021 for Vaccination site reaction, at an unspecified dose and frequency. At the time of the report, VACCINATION COMPLICATION (really bad side effects), ILLNESS (could "hardly get out of the bed"/sicker than a dog), ERYTHEMA (down to almost elbow was red as a beet), PERIPHERAL SWELLING (left arm from shoulder blade down to almost elbow was very swollen), INDURATION (left arm from shoulder blade down to almost elbow was hard), ERYTHEMA (inside of he left arm there is some redness that is travelling down arm), ALLERGY TO VACCINE (must be allergic to something (in booster)/made her afraid) and PYREXIA (full of fever) outcome was unknown and VACCINATION SITE REACTION (COVID Arm) was resolving.            No concomitant medication was reported. Patient went to see a nurse practitioner and was diagnosed with COVID Arm.Treatment medication include oral Benadryl (every 4 hours) and topical spray Benadryl and ice. The patient reported that the arm started to get better and wasn't as swollen as on 18-DEC-2021.   This case was linked to MOD-2021-418877 (Patient Link).   Reporter did not allow further contact