The breathlessness continued/ was in trouble, because of shortness of breath/ breathless when walked & talked; My legs would give way on me; This spontaneous case was reported by a consumer and describes the occurrence of DYSPNOEA (The breathlessness continued/ was in trouble, because of shortness of breath/ breathless when walked & talked) in an 81-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch no. 007M20A) for COVID-19 vaccination. The occurrence of additional non-serious events is detailed below.     Concurrent medical conditions included Diabetic and Heartbeats irregular (since patient was 20yo.). Concomitant products included IRON and CALCIUM for an unknown indication.   On 20-Feb-2021, the patient received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) 1 dosage form. On 20-Mar-2021, received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (unknown route) dosage was changed to 1 dosage form. On 20-Mar-2021,  after starting mRNA-1273 (Moderna COVID-19 Vaccine), the patient experienced DYSPNOEA (The breathlessness continued/ was in trouble, because of shortness of breath/ breathless when walked & talked) (seriousness criterion medically significant) and LIMB DISCOMFORT (My legs would give way on me). At the time of the report, DYSPNOEA (The breathlessness continued/ was in trouble, because of shortness of breath/ breathless when walked & talked) had not resolved and LIMB DISCOMFORT (My legs would give way on me) outcome was unknown.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 16-Apr-2021, Electrocardiogram: normal (normal) didn't find anything wrong. In 2021, Oxygen saturation: 97 and 98 (normal) 97 and 98. On 19-Jun-2021, SARS-CoV-2 test: negative (Negative) nasal and blood test, both were negative.         On 20 Mar 2021, patient started using walker. On 16 Apr 2021, patient's daughter took her to the emergency room due to shortness of breath. On 19 Aug 2021, patient's daughter took her to the emergency room again due to shortness of breath. The primary care physician did many tests and couldn't find anything wrong. Patient reported that patient had goods and bad days.  Company Comment: This case concerns an 81year-old, female patient with a history of heart rate irregular and diabetes, who experienced the serious unexpected event of dyspnoea. The event occurred the same day after the second dose of Moderna COVID-19 vaccine. The rechallenge was not assessable. The medical history, of heart rate irregular and diabetes, remain as confounders. The benefit-risk relationship of Moderna COVID-19 vaccine is not affected by this report.   This case was linked to MOD-2021-274485 (Patient Link).; Sender's Comments: This case concerns an 81year-old, female patient with a history of heart rate irregular and diabetes, who experienced the serious unexpected event of dyspnoea. The event occurred the same day after the second dose of Moderna COVID-19 vaccine. The rechallenge was not assessable. The medical history, of heart rate irregular and diabetes, remain as confounders. The benefit-risk relationship of Moderna COVID-19 vaccine is not affected by this report.