the patient ended up with tachycardia "in the 150's" then ended up in the  hospital/ the patient was diagnosed with postural orthostatic  tachycardia; This spontaneous case was reported by a physician and describes the occurrence of POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (the patient ended up with tachycardia "in the 150's" then ended up in the  hospital/ the patient was diagnosed with postural orthostatic  tachycardia) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 immunisation.    Co-suspect product included non-company product TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) for an unknown indication.    No Medical History information was reported.   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 dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. and dose of TOZINAMERAN (PFIZER BIONTECH COVID-19 VACCINE) (unknown route) 1 dosage form. On an unknown date, the patient experienced POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (the patient ended up with tachycardia "in the 150's" then ended up in the  hospital/ the patient was diagnosed with postural orthostatic  tachycardia) (seriousness criterion hospitalization). At the time of the report, POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (the patient ended up with tachycardia "in the 150's" then ended up in the  hospital/ the patient was diagnosed with postural orthostatic  tachycardia) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On an unknown date, Heart rate: had a mild increase in the tachycardia and tachycardia "in the 150's".     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter did not provide any causality assessments.   It was reported that after Moderna COVID-19 vaccine dose 2 and booster, the patient ended up with tachycardia "in the 150's" then ended up in the hospital.  Sometime after that, the patient was diagnosed with postural orthostatic tachycardia and had to be treated with beta blockers.  On an unreported date, following the 1st Moderna booster, the patient started treatment with Pfizer BioNTech COVID-19 vaccine, and had a mild increase in the tachycardia, but it was not as severe. It lasted for months, and then "it kind of went down to baseline, but still requires beta blockers." Two years later, the patient was still on beta blockers. Concomitant medications name were not reported.  No treatment medication name was provided  This is a spontaneous case concerning a female patient of unknown age, with no reported medical history, who experienced the unexpected serious (hospitalization) AESI of Postural orthostatic tachycardia syndrome. The event occurred twice after the administration of mRNA-1273 vaccine, used as a second and booster dose.  The patient ended up with tachycardia of about 150 beats per minute which then ended up in the hospital. She was treated with beta blockers. No further information on clinical course and investigations done was available in the report. The benefit-risk relationship of mRNA-1273 Vaccine is not affected by this report.