COVID-19; Thrombocytopenia/ Platelets146000; This spontaneous case was reported by a nurse and describes the occurrence of THROMBOCYTOPENIA (Thrombocytopenia/ Platelets146000) in a 65-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 045J21A, 04B21A and 046A21A) for COVID-19 prophylaxis. The occurrence of additional non-serious events is detailed below.     The patient's past medical history included Hepatic enzyme and Ex-smoker (Former smoker). Concurrent medical conditions included Oligodendroglioma (Chemotherapy round ended on 24-MAY-2022, did not take round starting from 18-Jul-2022.), Penicillin allergy, Hypertension and Asthma (Worsened during COVID-19 infection). Concomitant products included LEVOTHYROXINE from 01-Jan-2000 to an unknown date, MONTELUKAST from 01-Jan-2020 to an unknown date, LORATADINE from 01-Jan-2000 to an unknown date, AMLODIPINE from 01-Jan-2020 to an unknown date, FAMOTIDINE from 01-Jan-2020 to an unknown date, BUPROPION from 01-Jan-2020 to an unknown date, SALBUTAMOL SULFATE (PROAIR [SALBUTAMOL SULFATE]) and FLUTICASONE FUROATE, UMECLIDINIUM BROMIDE, VILANTEROL TRIFENATATE (TRELEGY ELLIPTA) for an unknown indication.   On 17-Mar-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On 14-Apr-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 10-Dec-2021, received third dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 11-Jul-2022,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced THROMBOCYTOPENIA (Thrombocytopenia/ Platelets146000) (seriousness criterion medically significant). On 14-Jul-2022, the patient experienced COVID-19 (COVID-19). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) from 15-Jul-2022 to 20-Jul-2022 for COVID-19 treatment, at a dose of daily; AZITHROMYCIN from 27-Jul-2022 to 31-Jul-2022 for COVID-19 treatment, at a dose of 2 daily for one day, then 1 daily for 4 days and PREDNISONE from 27-Jul-2022 to 31-Jul-2022 for COVID-19 treatment, at a dose of 20 milligram once a day. At the time of the report, THROMBOCYTOPENIA (Thrombocytopenia/ Platelets146000) outcome was unknown and COVID-19 (COVID-19) had resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 11-Jul-2022, Alanine aminotransferase: 32, normal. On 11-Jul-2022, Aspartate aminotransferase: 24, normal. On 11-Jul-2022, Blood creatinine: 0.72, normal. On 11-Jul-2022, Glomerular filtration rate: 93, normal. On 11-Jul-2022, Haemoglobin: 14.7. On 11-Jul-2022, Lymphocyte count (0.7-3.1): 0.7. On 11-Jul-2022, Neutrophil count (1.4-7): 3.2. On 11-Jul-2022, Platelet count (150000-450000): 146000. On 14-Jul-2022, SARS-CoV-2 test: (Positive) Positive, Nasal swab. On 24-Jul-2022, SARS-CoV-2 test: (Negative) Negative. On 25-Jul-2022, SARS-CoV-2 test: (Positive) Positive. On 03-Aug-2022, SARS-CoV-2 test: (Negative) Negative. On an unknown date, Body temperature: 101 101 degree F. On an unknown date, SARS-CoV-2 antibody test: Patient had antibodies at diagnosis- Checked by PCP.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   It was reported that the patient was not taking any other medications/products within 2 weeks of starting COVID-19 treatment. The patient had previously received a COVID-19 Vaccine. Device Date reported as 25-Jul-2022. Felt better after taking Paxlovid except for the cough still persisted. After stopping Paxlovid patient had rebound next day with tiredness, sore throat and fever.  On 06-Jul-2022, imaging for Covid-Pneumonia was negative for PNA. Patient took antihistamines.It was unknown if patient had any gastrointestinal/Hepatic, renal, vascular and neurological disorders.  Company comment: This spontaneous case concerns a 65-year-old female patient with Concurrent medical condition of Oligodendroglioma (Chemotherapy), who experienced the unexpected serious (medically significant) AESI of Thrombocytopenia and unexpected non-serious AESI of COVID-19. The event Thrombocytopenia occurred 7 months 1 day after and the event COVID-19 occurred 7 months 4 days after the third dose of mRNA-1273 vaccine in covid-19 vaccination series. Patient was treated with Paxlovid for days and tested negative 9 days after testing positive (24-Jul-2022), but she had rebound next day with tiredness, sore throat and fever and tested positive and tested negative 9 days later.  (SARS-CoV-2 test was Positive on 01-Jul-2022 (approximately 6 months after the third dose of mRNA-1273 vaccine). Patient also treated with Azithromycin and Prednisone for 5 days. Investigations like Alanine aminotransferase, Aspartate aminotransferase, Blood creatinine, Glomerular filtration rate, Haemoglobin, Lymphocyte count, Neutrophil count were reported as normal and Platelet count (150000-450000): 146000 decreased as on 11-Jul-2022. On an unknown date SARS-CoV-2 antibody test: Patient had antibodies at diagnosis- Checked by PCP. The outcome of the event Thrombocytopenia reported as unknown, and the event COVID-19 as resolved. Patients medical history of Oligodendroglioma (Chemotherapy) could be confounding for the event Thrombocytopenia. 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.   Most recent FOLLOW-UP information incorporated above includes: On 17-Aug-2022: Significant follow up received, event , lab data , narrative , medical history, medications and narrative updated.; Sender's Comments: This spontaneous case concerns a 65-year-old female patient with Concurrent medical condition of Oligodendroglioma (Chemotherapy), who experienced the unexpected serious (medically significant) AESI of Thrombocytopenia and unexpected non-serious AESI of COVID-19. The event Thrombocytopenia occurred 7 months 1 day after and the event COVID-19 occurred 7 months 4 days after the third dose of mRNA-1273 vaccine in covid-19 vaccination series. Patient was treated with Paxlovid for days and tested negative 9 days after testing positive (24-Jul-2022), but she had rebound next day with tiredness, sore throat and fever and tested positive and tested negative 9 days later.  (SARS-CoV-2 test was Positive on 01-Jul-2022 (approximately 6 months after the third dose of mRNA-1273 vaccine). Patient also treated with Azithromycin and Prednisone for 5 days. Investigations like Alanine aminotransferase, Aspartate aminotransferase, Blood creatinine, Glomerular filtration rate, Haemoglobin, Lymphocyte count, Neutrophil count were reported as normal and Platelet count (150000-450000): 146000 decreased as on 11-Jul-2022. On an unknown date SARS-CoV-2 antibody test: Patient had antibodies at diagnosis- Checked by PCP. The outcome of the event Thrombocytopenia reported as unknown, and the event COVID-19 as resolved. Patients medical history of Oligodendroglioma (Chemotherapy) could be confounding for the event Thrombocytopenia. 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.