Patient received second dose on 02-Jun-2021 and received 1st booster on 03-Sep-2021; vaccination adverse reaction; This spontaneous case was reported by a patient family member or friend and describes the occurrence of VACCINATION COMPLICATION (vaccination adverse reaction) and INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received second dose on 02-Jun-2021 and received 1st booster on 03-Sep-2021) in an 83-year-old male patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 014C21A, 039B21A and 003C21A) for COVID-19 prophylaxis.     The patient's past medical history included COVID-19 (not hospitalized) and Esophagogastroduodenoscopy. Concurrent medical conditions included Heartbeats skipped (Heart (skip in his heart)), Diabetes mellitus (Diabetic for long time), Atherosclerosis of aorta, Carotid artery disease (Carotid artery plaque), Allergic rhinitis, Atrial flutter, Diabetic nephropathy (Diabetes mellitus with diabetic nephropathy), Hyperlipidemia, Barrett's oesophagus, Major depressive disorder (single episode; unspecified), Primary open angle glaucoma (both eyes), Type 2 diabetes mellitus (with complications), Type II diabetes mellitus with renal manifestations (Diabetes mellitus type 2 with Renal disease) and Diabetic polyneuropathy. Concomitant products included FLUTICASONE PROPIONATE (FLUTICASONE PROPRIONATE) from 21-Jan-2008 to an unknown date for Allergic rhinitis, APIXABAN (ELIQUIS) from 20-Dec-2018 to an unknown date for Atherosclerosis of aorta and Carotid artery disease, SOTALOL HCL from 12-Dec-2018 to an unknown date for Atrial flutter, OMEPRAZOLE from 22-Nov-2010 to an unknown date for Barrett's oesophagus, GLIMEPIRIDE (AMARYL) from 05-Dec-2011 to an unknown date and METFORMIN HCL from 26-Apr-2021 to an unknown date for Diabetes mellitus and Diabetic nephropathy, EXENATIDE (BYDUREON BCISE) from 24-Jan-2019 to an unknown date and GABAPENTIN from 24-Jan-2022 to an unknown date for Diabetes mellitus and Diabetic polyneuropathy, MULTIVITAMINS [VITAMINS NOS] from 03-Jul-2014 to an unknown date for Esophagogastroduodenoscopy, SIMVASTATIN from 25-Jul-2008 to an unknown date for Hyperlipidemia, DULOXETINE HYDROCHLORIDE (CYMBALTA) from 15-Dec-2014 to an unknown date for Major depressive disorder, LATANOPROST from 28-Aug-2015 to an unknown date for Primary open angle glaucoma, VITAMIN B6 from 27-Jan-2016 to an unknown date for an unknown indication.   On 05-May-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 02-Jun-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 03-Sep-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. In 2021, the patient experienced VACCINATION COMPLICATION (vaccination adverse reaction). On 03-Sep-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received second dose on 02-Jun-2021 and received 1st booster on 03-Sep-2021). In 2021, VACCINATION COMPLICATION (vaccination adverse reaction) had resolved. At the time of the report, INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received second dose on 02-Jun-2021 and received 1st booster on 03-Sep-2021) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 25-Jan-2021, SARS-CoV-2 test: (Positive) Positive.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered VACCINATION COMPLICATION (vaccination adverse reaction) to be related. No further causality assessment was provided for INAPPROPRIATE SCHEDULE OF PRODUCT ADMINISTRATION (Patient received second dose on 02-Jun-2021 and received 1st booster on 03-Sep-2021).    The patient had no allergies.  Patient was instructed to use contour next step in vitro strip to check sugars 2-3 times daily as indicated for diabetes mellitus type 2 with complication on 17-Oct-2016 and also received lancet ultrafine 30 gram three times daily for Diabetes mellitus type 2 causing renal disease on 21-Oct-2013.  The patient was on a bunch of medications but did not provide any names.  No treatment medications were reported.   This case was linked to (Patient Link).