booster-had supraventricular tachycardia; Could not get his blood pressure reading; booster-felt woozy; had Covid/had a nasty head cold to the chest; This spontaneous case was reported by a patient and describes the occurrence of SUPRAVENTRICULAR TACHYCARDIA (booster-had supraventricular tachycardia), BLOOD PRESSURE IMMEASURABLE (Could not get his blood pressure reading) and DIZZINESS (booster-felt woozy) in a male patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     No Medical History information was reported.   On an unknown date, the patient received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form and first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On an unknown date, the patient experienced SUPRAVENTRICULAR TACHYCARDIA (booster-had supraventricular tachycardia) (seriousness criterion medically significant), BLOOD PRESSURE IMMEASURABLE (Could not get his blood pressure reading) (seriousness criterion medically significant), DIZZINESS (booster-felt woozy) (seriousness criterion medically significant) and COVID-19 (had Covid/had a nasty head cold to the chest). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) at a dose of 1 dosage form. At the time of the report, SUPRAVENTRICULAR TACHYCARDIA (booster-had supraventricular tachycardia), BLOOD PRESSURE IMMEASURABLE (Could not get his blood pressure reading), DIZZINESS (booster-felt woozy) and COVID-19 (had Covid/had a nasty head cold to the chest) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Blood pressure measurement: could not get his blood pressure reading could not get his blood pressure reading. On an unknown date, Heart rate: 230 beats a min 230 beats a min.         Concomitant medications were not reported.   The patient stated that he had three shots of Moderna and had SVT with the Moderna booster six days after on Christmas Eve at 230 beats a minute. It was reported that the previous day he had the virus and told him about a medication called Paxlovid. It was stated that he had COVID.  It was reported hat he had nothing with the other ones but after the booster six days later he had event which was later clarified as supraventricular tachycardia. The patient felt woozy and could not get his blood pressure reading. Stated that they gave him a drip and that he was lucky to be alive.   It was stated that there was a product complaint to report Moderna.  Company comment-This spontaneous case concerns a male patient (age not specified) with no medical history reported, who experienced the unexpected serious (medically significant) events of Supraventricular tachycardia (AESI), Dizziness and Blood pressure immeasurable and unexpected non-serious AESI of Covid 19 on unknown dates after receiving booster dose (3rd dose) of mRNA-1273 vaccine in the covid 19 vaccination series. Patient had received 3 doses of Moderna vaccine on unknown dates and experienced Supraventricular tachycardia 6 days after the booster dose with heart rate of 230 beats per min. He had dizziness and his blood pressure was not recordable. He was treated with drip, felt better and further details not reported. He was diagnosed to have Covid with a nasty head cold to chest on an unknown date. No further details on clinical course, lab test results and treatment received were reported. Outcome of the events was not known at the time of report. The current pandemic situation of COVID 19 may remain as confounder to the event Covid-19. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. Events seriousness assessed as per medical judgement.   Reporter did not allow further contact; Sender's Comments: This spontaneous case concerns a male patient (age not specified) with no medical history reported, who experienced the unexpected serious (medically significant) events of Supraventricular tachycardia (AESI), Dizziness and Blood pressure immeasurable and unexpected non-serious AESI of Covid 19 on unknown dates after receiving booster dose (3rd dose) of mRNA-1273 vaccine in the covid 19 vaccination series. Patient had received 3 doses of Moderna vaccine on unknown dates and experienced Supraventricular tachycardia 6 days after the booster dose with heart rate of 230 beats per min. He had dizziness and his blood pressure was not recordable. He was treated with drip, felt better and further details not reported. He was diagnosed to have Covid with a nasty head cold to chest on an unknown date. No further details on clinical course, lab test results and treatment received were reported. Outcome of the events was not known at the time of report. The current pandemic situation of COVID 19 may remain as confounder to the event Covid-19. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report. Events seriousness assessed as per medical judgement.