COVID-19 positive before second dose; Lower back pain after the first dose for a week; This spontaneous case was reported by an other health care professional and describes the occurrence of BACK PAIN (Lower back pain after the first dose for a week) and COVID-19 (COVID-19 positive before second dose) in a 40-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) for COVID-19 vaccination.     Concurrent medical conditions included Reaction to preservatives (Food preservative), Seasonal allergy (Regular) and Immunocompromised. Concomitant products included DICLOFENAC for Antiinflammatory therapy.    In April 2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) .5 milliliter. In April 2021, the patient experienced BACK PAIN (Lower back pain after the first dose for a week). In May 2021, the patient experienced COVID-19 (COVID-19 positive before second dose). In 2021, BACK PAIN (Lower back pain after the first dose for a week) had resolved. At the time of the report, COVID-19 (COVID-19 positive before second dose) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): In May 2021, SARS-CoV-2 test: positive (Positive) Positive.     mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosing remained unchanged.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   The patient did not take any other vaccines at the time of report.  The patient received her vaccine at left arm (non-dominant). The patient reported that she may had COVID-19 later on after second dose, but not positive and was not sure of exact date.  No treatment medications were reported.  Company Comment: This is a Spontaneous case concerning a 40-year-old female patient, with reported medical history of Immunodeficiency, who experienced the serious unexpected AESI of COVID-19. The event occurred in an unknown date during the next month after the administration of the first dose of the mRNA-1273 vaccine. In this case, there is reported the administration of the second dose of the vaccine, the same month of the onset of the adverse event of COVID-19, but there is limited information regarding dose dates and event dates. The reported medical history remains as a confounder for the event. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report. The case was assessed as non-serious.   This case was linked to MOD-2022-508757 (Patient Link).; Sender's Comments: This is a Spontaneous case concerning a 40-year-old female patient, with reported medical history of Immunodeficiency, who experienced the serious unexpected AESI of COVID-19. The event occurred in an unknown date during the next month after the administration of the first dose of the mRNA-1273 vaccine. In this case, there is reported the administration of the second dose of the vaccine, the same month of the onset of the adverse event of COVID-19, but there is limited information regarding dose dates and event dates. The reported medical history remains as a confounder for the event. The benefit-risk relationship of the mRNA-1273 vaccine is not affected by this report. The case was assessed as non-serious.