Abstract
A septuagenarian woman developed dyspnea on the day following a fifth vaccination. Just before vaccination, a chest X-ray showed no abnormalities, but after the fifth vaccination, bilateral diffuse ground-glass opacities were detected. Bronchoalveolar lavage revealed a lymphocyte predominance and transbronchial lung biopsy revealed growth of the alveolar epithelium, along with organized polypoid granulation tissues in the alveolar ducts and bronchioles. Despite the administration of corticosteroids, imaging revealed persistent fibrosis, and she required long-term oxygen therapy. Although recent reports indicated that corticosteroids are effective for drug-induced interstitial lung disease related to COVID-19 mRNA vaccination, this case presented a somewhat different clinical manifestation.