Case Presentation: We describe a 56-year-old man who presented with a three-week-history of dyspnea. The dyspnea began two days following the first dose of a two-part Moderna COVID-19 vaccination series. In the three weeks prior to presentation, he had sought help at an urgent care, and from his primary care physician, and was treated with azithromycin, and levofloxacin, respectively, for presumed pneumonia, with no response to either antibiotic. He reported nonproductive cough, and denied fever, chills, weight loss, and rashes. His other problems were hypertension, and alcoholic cirrhosis with a model for end-stage liver disease score of 10. At presentation, oxygen saturation was 86% on ambient air, and improved to 92% with supplemental oxygen at 3 liters per min. Other vital signs were stable. Examination was notable for bilateral expiratory wheezing, and otherwise normal. Labs showed leukocytes of 8160 cells/mm3 with 23% eosinophils, and platelets of 90,000 cells/mm3. Comprehensive metabolic panel, cardiac markers, and urinalysis were normal. Computerized tomography of the chest showed bilateral ground glass opacities. The patient was treated with empiric high-dose steroids for the first two days of hospitalization with some improvement; peripheral eosinophils dropped to 0%. A SARS-CoV-2 nasopharyngeal PCR assay, autoimmune serologies, and serologies for Legionella, Strongyloides, Coccidioides, and Histoplasma were all negative. Due to concern for acute eosinophilic pneumonia (AEP), pulmonology was consulted, steroids held, and a bronchoscopy was performed. Bronchoalveolar lavage (BAL) fluid analysis revealed 8% eosinophils. As the diagnostic BAL eosinophil threshold for AEP is 25%, he was not treated with steroids at this point. Serum IgE titer was 1527 kilo IU/L. BAL was negative for Aspergillus galactomannan. Given the negative work-up for other etiologies, the diagnosis of acute eosinophilic pneumonia was made. Over the next three days, the patient remained symptomatic, and hypoxemic. Furthermore, peripheral eosinophilia increased from 0% to 24%. Treatment was initiated with a single dose of methylprednisolone 40 milligrams with clinical improvement, and resolution of eosinophilia in 36 hours. The patient was then placed on oral prednisone at 40 milligrams per day, and prednisone was tapered over two weeks. He remained in remission following cessation of steroids.
Discussion: AEP presents with a short febrile illness, hypoxemic respiratory failure, and diffuse lung opacities. Diagnostic criteria include a BAL differential with greater than 25% eosinophils, and no other etiology for the eosinophilia. Our patient met all criteria with the single exception of the degree of BAL eosinophilia, which can be explained by the initial drop in eosinophils due to the empiric steroids given at admission. An outpatient follow-up with our allergy-immunology clinic was arranged prior to discharge.
Conclusions: While AEP has been described following other vaccinations such as the influenza, and pneumococcal vaccines, we describe the first known case of AEP following COVID vaccination. We instructed our patient to hold off on taking further mRNA vaccines (including both the Moderna, and Pfizer formulations), and suggested that he consider the Janssen formulation which uses a viral vector, instead.