Abstract
BACKGROUND: The H5N1 influenza virus is a cause of severe pneumonia. Co-infection of influenza virus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may lead to poor prognosis of patients during the COVID-19 epidemic. However, reports on patients co-infected with avian influenza virus and SARS-CoV-2 are scarce. CASE PRESENTATION: A 52-year-old woman presented with a fever, which has persisted for the past eight days, along with worsening shortness of breath and decreased blood pressure. Computed tomography (CT) revealed an air bronchogram, lung consolidation, and bilateral pleural effusion. The subsequent polymerase chain reaction (PCR) of the bronchoalveolar lavage fluid (BALF) revealed positivity for H5N1 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). CONCLUSION: The H5N1 influenza virus is a cause of severe pneumonia. The clinical presentation of the patient had a predomination of H5N1 influenza rather than COVID-19. A PCR analysis for the identification of the virus is necessary to reveal the pathogen causing the severe pneumonia. The patient exhibited an excellent prognosis upon the use of the appropriate antiviral medicine.