Pleural effusion; Cough; Dyspnoea; This case was received on 15-Jun-2021 and was forwarded to Moderna on 15-Jun-2021.    This regulatory authority case was reported by an other health care professional and describes the occurrence of PLEURAL EFFUSION (Pleural effusion), LUNG OPACITY (Lung opacity), COUGH (Cough), DYSPNOEA (Dyspnoea) and HILAR LYMPHADENOPATHY (Hilar lymphadenopathy) in a 65-year-old female patient who received mRNA-1273 (Moderna COVID-19 Vaccine) (batch nos. 044B21A and 027C21A) for COVID-19 vaccination.     The patient's past medical history included Lung cancer (relapse in 2010 tx with radiation- in remission) in 2007. Concurrent medical conditions included Diabetes mellitus (diabetes mellitus  type 2), Tobacco user, Neuropathy, Hyperlipidemia and Restless leg syndrome. Concomitant products included ATORVASTATIN CALCIUM (LIPITOR), GABAPENTIN, IRBESARTAN, ROPINIROLE, INSULIN GLARGINE (LANTUS), METOPROLOL and MONTELUKAST SODIUM (SINGULAIR) for an unknown indication.   On 12-May-2021, the patient received second dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) 1. On 12-May-2021, received first dose of mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular) dosage was changed to 1 dosage form. On 16-May-2021, the patient experienced PLEURAL EFFUSION (Pleural effusion) (seriousness criterion hospitalization), LUNG OPACITY (Lung opacity) (seriousness criterion hospitalization), COUGH (Cough) (seriousness criterion hospitalization), DYSPNOEA (Dyspnoea) (seriousness criterion hospitalization) and HILAR LYMPHADENOPATHY (Hilar lymphadenopathy) (seriousness criterion hospitalization). At the time of the report, PLEURAL EFFUSION (Pleural effusion), LUNG OPACITY (Lung opacity), COUGH (Cough), DYSPNOEA (Dyspnoea) and HILAR LYMPHADENOPATHY (Hilar lymphadenopathy) had not resolved.      DIAGNOSTIC RESULTS (normal ranges are provided in parenthesis if available): On 16-May-2021, Aspiration pleural cavity: Inconclusive. On 16-May-2021, Computerised tomogram thorax: (abnormal) CT chest showed Vague ground-glass opacities left lung base possibly representing pneumonitis or atelectasis. On 16-May-2021, Cytology: (abnormal) cytology was significant for reactive mesothelial cells and negative for any malignancy. On 16-May-2021, Full blood count: normal. On 16-May-2021, Metabolic function test: normal. On 16-May-2021, SARS-CoV-2 test: Negative.     For mRNA-1273 (Moderna COVID-19 Vaccine) (Intramuscular), the reporter did not provide any causality assessments.   No treatment product information was provided.  Patient was vaccinated on 12 Apr 2021 and 12 May 2021 and presented to the emergency department on 15 May 2021 with complaint of worsening shortness of breath and cough. According to the patient her shortness of breath started couple of weeks back just after her first covid vaccine but it got worse in the last few days following her second vaccine. Imaging revealed a large R pleural effusion. A thoracentesis was done and she was sent home. She was tested and was covid negative. Cytology was significant for reactive mesothelial cells and negative for any malignancy. CT chest showed Vague ground-glass opacities left lung base possibly representing pneumonitis or atelectasis. Confluent right hilar lymphadenopathy and a large effusion was seen she was discharged home to follow up with her doctor on 17 Apr 2021.; Sender's Comments: Based on the current available information and temporal association between the use of the product and the start date of the events, a causal relationship cannot be excluded.  The patient's comorbidities remains as confounders.