This is a literature report. A 75-year-old woman with past medical history of atrial fibrillation, hypertension, and remotely treated breast cancer presented with dyspnea, non-productive cough, subjective fevers, polyarthralgias, myalgias, and consequent sleep disturbance of 10 days duration. Her medications were hydrochlorothiazide, losartan and simvastatin. Eighteen days earlier she had been seen for a routine health-care visit and received PCV13. Soon thereafter she developed a large, erythematous, warm local reaction to the vaccine, which was still present. Her vital signs included a pulse rate of 126 beats/minute, blood pressure of 99/ 63 mmHg, a maximum temperature of 36.6 degrees Celsius, and oxygen saturation of 83% on room air requiring bilevel positive airway pressure therapy. She had reduced breath sounds in the left lung field. Her white blood cell (WBC) count was 19.1 (normal 4-11 K/uL), creatinine level was 1.5 (normal 0.52-1.04 mg/dL), and B-type natriuretic peptide level was 1670 (normal 0-900 pg/mL). All blood bacterial cultures, urine streptococcus pneumonia and legionella antigens, mycoplasma titers, and Lyme antibody test results were negative. A chest X-ray and computed tomography (CT) scan showed a large left pleural effusion and a large pericardial effusion. An echocardiogram confirmed the pericardial effusion. Her erythrocyte sedimentation rate (ESR) was 59 (normal 0-20 mm/hour), C-reactive protein (CRP) level was 62.7 (normal 0-0.9 mg/dL), and her rheumatoid factor was 15 (normal 0-11 IU/mL). Her antinuclear antibody test result was negative. Test results for anti-Sm, -double stranded deoxyribonucleic acid (dsDNA), -histone, -cardiolipin, -ribonucleoprotein, -centromere, -topoisomerase I, -Ro, -La, -thyroid, -neutrophil cytoplasmic (-myeloperoxidase and -proteinase 3) antibodies were all negative. Her complement levels were normal. Thoracentesis and pericardial window were required. Pleural fluid appeared bloody and was exudative by Light's criteria (serum lactate dehydrogenase [LDH] 765 U/L, serum total protein 7.7 g/dL; pleural LDH 749 U/L, red blood cells 320,000/uL, nucleated cells 3368/uL [PMN 62%, lymphocytes 22%, macrophages/histiocytes 14%, mesothelial cells 2%], glucose 97 mg/dL) . Cytology test results of the pleural fluid were negative. The pericardial fluid was exudative and hemorrhagic and cultures and cytology test results were negative. A pericardial biopsy showed organizing effusion containing hemorrhage and acute inflammation with reactive changes and mesothelial hyperplasia. Cultures of the pericardial biopsy were negative. The pleural fluid re-accumulated so a chest tube was placed. Repeat fluid analysis was similar and cultures were negative. Given the severity of her illness, her serositis was treated with corticosteroids rather than nonsteroidal antiinflammatory medications. She received 40 mg of prednisone daily for 2 weeks with a good initial response and tapered off steroids over the next 3 months. Her vital signs recovered to normal range throughout the admission. The chest tube and pericardial drain were removed prior to discharge. A follow-up chest X-ray one year after discharge revealed no recurring pleural effusions. She has remained asymptomatic now for one and a half years since discharge. This patient had a severe focal skin reaction to the vaccine and progressively developed polyarthralgias, myalgias, and finally marked serositis of the pleura and pericardium. The temporal association, the absence of identifiable infective or neoplastic etiologies, and improvement with steroids suggests a reaction to the vaccine. Thus, this report documents the first systematic inflammatory reaction to PCV13 in a patient without previous autoimmune disease.  In summary, while immunization with PCV13 is highly recommended, rarely an auto-inflammatory response may occur. Pfizer is a marketing authorization holder of pneumococcal 13-val conj vac (dipht crm197 protein) in the reporter's country. This may be a duplicate report if another marketing authorization holder of pneumococcal 13-val conj vac (dipht crm197 protein) has submitted the same report to the regulatory authorities.; Sender's Comments: A possible contributory role of the suspect product cannot be excluded for the reported events of serositis, polyarthralgias, myalgias and skin reaction, based on the temporal association and clinical course of the events. The impact of this report on the benefit/risk profile of the Pfizer product is evaluated as part of Pfizer procedures for safety evaluation, including the review and analysis of aggregate data for adverse events. Any safety concern identified as part of this review, as well as any appropriate action in response, will be promptly notified to Regulatory Authorities, Ethics Committees and Investigators as appropriate.