This spontaneous case was reported by a physician and describes the occurrence of COVID-19 (COVID-19) in a female patient of an unknown age who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. O25J20A) for COVID-19 vaccination. The patient's past medical history included Depression. Previously administered products included for Drug use for unknown indication: amoxicillin, mirtazapine, sulfa, quetiapine (quetiapine) and morphine. Past adverse reactions to the above products included Allergy with amoxicillin, mirtazapine, morphine, quetiapine, and sulfa. Concurrent medical conditions included Sjogren's and Gastrointestinal stromal tumor. On 03-Dec-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1 dosage form. On an unknown date, the patient experienced COVID-19 (COVID-19). The patient was treated with NIRMATRELVIR, RITONAVIR (PAXLOVID) (oral) from 20-Apr-2022 to 25-Apr-2022 for COVID-19, at an unspecified dose and frequency. At the time of the report, COVID-19 (COVID-19) outcome was unknown. The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) was unknown. For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments. No concomitant product was provided. Patient had received other medications/products within 2 weeks of starting COVID-19 treatment. From 20-Apr-2022, Patient noted weakness in lower extremities upon starting Paxlovid and by the time she had completed 5 days course she could not walk and was admitted to hospital for 6 days and then discharged to rehab for another 6 days. Supportive care treatment received for adverse event. Company comment: This spontaneous case concerns a female patient of unknown age, with no known relevant medical history, who experienced unexpected, serious (hospitalized) event of Muscular weakness and unexpected, non-serious, AESI of COVID-19, unspecified days, after receiving mRNA-1273 vaccine as a first dose. The patient was started with Nirmatrelvir-Ritonavir (Paxlovid) at unspecified dose and frequency for five days. The patient noted weakness in lower extremities upon starting with Paxlovid and by the time she had completed the five-day course, she could not walk, hence, was subsequently admitted to a hospital for 6 days. The patient was then discharged and underwent rehab for another 6 days. The patient received unspecified supportive care treatment.  At the time of the report, the outcome of the events was unknown. The benefit-risk relationship of mRNA-1273 is not affected by this report. Sender's Comments: This spontaneous case concerns a female patient of unknown age, with no known relevant medical history, who experienced unexpected, serious (hospitalized) event of Muscular weakness and unexpected, non-serious, AESI of COVID-19, unspecified days, after receiving mRNA-1273 vaccine as a first dose. The patient was started with Nirmatrelvir-Ritonavir (Paxlovid) at unspecified dose and frequency for five days. The patient noted weakness in lower extremities upon starting with Paxlovid and by the time she had completed the five-day course, she could not walk, hence, was subsequently admitted to a hospital for 6 days. The patient was then discharged and underwent rehab for another 6 days. The patient received unspecified supportive care treatment. At the time of the report, the outcome of the events was unknown. The benefit-risk relationship of mRNA-1273 is not affected by this report.