fainted; felt sick; arm pain; received 3rd shot and is not immunocompromised; muscle pain; very weak; seems to be very hot; This spontaneous case was reported by a consumer and describes the occurrence of SYNCOPE (fainted) in an 8-decade-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 091D21A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On 12-Oct-2021, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 12-Oct-2021, the patient experienced VACCINATION SITE PAIN (arm pain), OFF LABEL USE (received 3rd shot and is not immunocompromised) and MYALGIA (muscle pain). On 13-Oct-2021, the patient experienced MALAISE (felt sick). On 14-Oct-2021, the patient experienced SYNCOPE (fainted) (seriousness criterion medically significant). In October 2021, the patient experienced ASTHENIA (very weak) and FEELING HOT (seems to be very hot). On 12-Oct-2021, OFF LABEL USE (received 3rd shot and is not immunocompromised) had resolved. At the time of the report, SYNCOPE (fainted), VACCINATION SITE PAIN (arm pain), ASTHENIA (very weak) and FEELING HOT (seems to be very hot) outcome was unknown and MALAISE (felt sick) and MYALGIA (muscle pain) had not resolved.            Concomitant medications was not reported. Treatment medications was not reported.  The patient was in her seventies.The patient had the 3rd Moderna COVID-19 vaccine shot and had a reaction. The patient felt sick after the shot, by the following day. She had arm pain pretty immediate, the same day. She had increasing weakness and seems to be very hot, she had been very weak all day. There was no such reaction to the first shots. She had muscle pain pretty soon after and that continued and was still not feeling fine. When asked if immunocompromised reporter did not know and assumed the 3rd dose included people over 65 years old as well. The side effects were so much different than the previous doses.  Company Comment: This case concerns a female patient in her seventies with no relevant medical history who experienced serious unexpected event of syncope. The events occurred approximately two days after the third dose of Spikevax. Reportedly, the patient felt sick with arm pain immediately after vaccination with increasing weakness and feeling hot. The patient got up to get a drink and fainted on the floor and was very weak all day. The patient also had muscle pain pretty soon after vaccination and that continued and she still feels unwell.  Rechallenge was not applicable as the event occurred after the third dose so no rechallenge was done and recurrence was not applicable.  The benefit-risk relationship of drug is not affected by this report   This case was linked to MOD-2021-354077, MOD-2021-354097, MOD-2021-354098, MOD-2021-353426 (Patient Link).   Most recent FOLLOW-UP information incorporated above includes: On 15-Oct-2021: Follow-up  received contains significant information: Batch number of booster dose was updated.; Sender's Comments: This case concerns a female patient in her seventies with no relevant medical history who experienced serious unexpected event of syncope. The events occurred approximately two days after the third dose of Spikevax. Reportedly, the patient felt sick with arm pain immediately after vaccination with increasing weakness and feeling hot. The patient got up to get a drink and fainted on the floor and was very weak all day. The patient also had muscle pain pretty soon after vaccination and that continued and she still feels unwell.  Rechallenge was not applicable as the event occurred after the third dose so no rechallenge was done and recurrence was not applicable.  The benefit-risk relationship of drug is not affected by this report