COVID-19 vaccine-associated organizing pneumonia.

We report the first case of organizing pneumonia (OP) associated with a new coronavirus disease (COVID-19) vaccination. A 78-year-old woman developed cough and dyspnoea 10 days after receiving BNT162b2. Chest computed tomography (CT) revealed consolidation in the bilateral lower lobes of the lungs. Although antibiotic treatment did not improve her symptoms, she received a second vaccination as scheduled. She was referred to our hospital because of worsening dyspnoea on day 9 after the second vaccination, with reversed halo signs in the bilateral lower pulmonary lobes and new consolidation in the left lingual region on chest CT on day 15. She was diagnosed with OP based on bronchoalveolar lavage and transbronchial lung biopsy findings. Treatment with oral prednisolone 0.5 mg/kg/day immediately improved the symptoms and chest imaging findings. In the absence of other triggering factors, we considered this case as being COVID-19 vaccine-associated following the first and second vaccinations.