Low platelet count; Fatigue; Body ache; Bad headache; Fever; Chills; Shaking; Soreness in the arm but little bit worse than 1st time; This spontaneous case was reported by a physician (subsequently medically confirmed) and describes the occurrence of THROMBOCYTOPENIA (Low platelet count) in a 36-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 032L20A and 026L20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Lupus nephritis (Platelet count has dropped significantly since receiving the vaccine; I have been put on a course of Prednisone) since January 2004 and Allergy to antibiotic (Amoxicillin). Concomitant products included LISINOPRIL from January 2021 to an unknown date for Nephritis, ACETYLSALICYLIC ACID (BABY ASPIRIN) from 2020 to an unknown date for Prevention, PRENATAL VITAMINS [ASCORBIC ACID;BETACAROTENE;CALCIUM SULFATE;COLECALCIFEROL;CYANOCOBALAMIN;FERROUS FUMARATE;FOLIC ACID;NICOTINAMIDE;PYRIDOXINE HYDROCHLORIDE;RETINOL ACETATE;RIBOFLAVIN;THIAMINE MONONITRATE;TOCOPHERYL ACETATE;ZINC OXIDE] from 2021 to an unknown date for Vitamin supplementation, VITAMIN D3 for an unknown indication.   On 22-Jan-2021 at 2:20 PM, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 19-Feb-2021 at 7:30 AM, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 19-Feb-2021, the patient experienced TREMOR (Shaking). 19-Feb-2021, the patient experienced VACCINATION SITE PAIN (Soreness in the arm but little bit worse than 1st time). On 19-Feb-2021 at 4:30 PM, the patient experienced CHILLS (Chills). On 20-Feb-2021, the patient experienced HEADACHE (Bad headache). On 20-Feb-2021 at 12:00 PM, the patient experienced FATIGUE (Fatigue) and MYALGIA (Body ache). In April 2021, the patient experienced THROMBOCYTOPENIA (Low platelet count) (seriousness criterion medically significant). The patient was treated with PARACETAMOL (TYLENOL EXTRA-STRENGTH) on 19-Feb-2021 for Adverse event, at a dose of 1 tablet and PARACETAMOL (TYLENOL EXTRA-STRENGTH) on 20-Feb-2021 for Adverse event, at a dose of 2 tablets. On 21-Feb-2021, TREMOR (Shaking), VACCINATION SITE PAIN (Soreness in the arm but little bit worse than 1st time), CHILLS (Chills), HEADACHE (Bad headache), FATIGUE (Fatigue) and MYALGIA (Body ache) had resolved. At the time of the report, THROMBOCYTOPENIA (Low platelet count) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 19-Feb-2021, Body temperature: 99.6 (Inconclusive) First a low grade fever with 99.6.  Around 8 or 9 pm, fever rose up to 102. In middle of the night, the temperature was 100.7.. On 20-Feb-2021, Body temperature: 104.4 (Inconclusive) high. In April 2021, Platelet count: decreased (Low) Decreased.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter considered TREMOR (Shaking), VACCINATION SITE PAIN (Soreness in the arm but little bit worse than 1st time), CHILLS (Chills), HEADACHE (Bad headache), FATIGUE (Fatigue) and MYALGIA (Body ache) to be possibly related. No further causality assessment was provided for THROMBOCYTOPENIA (Low platelet count).    The patient was treated with unspecified IV steroids.  Based on the current available information and temporal association between the use of the product, and the start date of the events, a causal relationship cannot be excluded. For the event Thrombocytopenia, current condition Lupus might be co-suspect/confounder   This case was linked to MOD-2021-041453.   Most recent FOLLOW-UP information incorporated above includes: On 23-Jun-2021: Follow-up information received on 23-jun-2021 contains information regarding the reporter, the patient demographics (height, weight, and ethnicity), allergic conditions, start date and batch number of first dose of Moderna vaccine, additional event of platelet count low and the case was upgraded to serious.; Sender's Comments: Based on the current available information and temporal association between the use of the product, and the start date of the events, a causal relationship cannot be excluded. For the event Thrombocytopenia, current condition Lupus might be co-suspect/confounder