both ankles started swelling, the right ankle larger than the left; I'd begun to feel fatigued during walk; This spontaneous case was reported by a consumer and describes the occurrence of JOINT SWELLING (both ankles started swelling, the right ankle larger than the left) and FATIGUE (I'd begun to feel fatigued during walk) in a 78-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 043L20A) for COVID-19 vaccination.     The patient's past medical history included Breast cancer (Have lymphedema in left arm from breast cancer in 1995.) in 1995, Kidney disorder and Poliomyelitis. Concurrent medical conditions included Lymphedema (Have lymphedema in left arm from breast cancer in 1995.) since 1995.    On 03-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On an unknown date, the patient experienced JOINT SWELLING (both ankles started swelling, the right ankle larger than the left) and FATIGUE (I'd begun to feel fatigued during walk). At the time of the report, JOINT SWELLING (both ankles started swelling, the right ankle larger than the left) and FATIGUE (I'd begun to feel fatigued during walk) outcome was unknown.        The action taken with mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown) was unknown.   For mRNA-1273 (Moderna COVID-19 Vaccine) (Unknown), the reporter considered JOINT SWELLING (both ankles started swelling, the right ankle larger than the left) and FATIGUE (I'd begun to feel fatigued during walk) to be possibly related.    Few weeks after vaccination, the patient began to feel fatigued during a walk on the beach. She also noticed that both ankles started swelling, the right ankle larger than the left.  Concomitant medication of the patient was not reported.  No treatment information was provided by the reporter.  Company Comment: This case concerns a 78-year-old, female subject with a medical history of poliomyelitis and unspecified kidney problems, who experienced the unexpected event of joint swelling and the expected event of fatigue. The events joint swelling and fatigue occurred a few weeks after administration of the first dose of the Moderna COVID-19 Vaccine. The rechallenge was not applicable as the events occurred after the first dose. The events were considered possibly related to the Moderna COVID-19 Vaccine per the reporter's assessment. The event fatigue is consistent with the current understanding of the mechanism of action of the Moderna COVID-19 Vaccine. The medical history of poliomyelitis (post-polio syndrome), which may cause fatigue, as well as unspecified kidney problems, which may cause swelling, remain as confounders. The benefit-risk relationship of the Moderna COVID-19 Vaccine is not affected by this report.   This case was linked to MOD-2021-320764 (Patient Link).; Sender's Comments: This case concerns a 78-year-old, female subject with a medical history of poliomyelitis and unspecified kidney problems, who experienced the unexpected event of joint swelling and the expected event of fatigue. The events joint swelling and fatigue occurred a few weeks after administration of the first dose of the Moderna COVID-19 Vaccine. The rechallenge was not applicable as the events occurred after the first dose. The events were considered possibly related to the Moderna COVID-19 Vaccine per the reporter's assessment. The event fatigue is consistent with the current understanding of the mechanism of action of the Moderna COVID-19 Vaccine. The medical history of poliomyelitis (post-polio syndrome), which may cause fatigue, as well as unspecified kidney problems, which may cause swelling, remain as confounders. The benefit-risk relationship of the Moderna COVID-19 Vaccine is not affected by this report.