CASE REPORT

Case 1
10-month-old boy presented with fever for 3 hours and was admitted to the Fever Clinic of the Beijing Haidian Hospital. His parents and sister were confirmed with COVID-19 2 days before. They contracted it after having dinner with a family friend who had recently returned from Wuhan. Physical examination showed fever with a peak body temperature of 38℃ that returned to normal by itself. Laboratory examination showed normal leukocyte (9.32 × 109/L) and neutrophil (1.93 × 109/L) counts, increased differential count of lymphocytes (68.8%), and an elevated C-reactive protein level (11 mg/L).
The patient had been admitted to the Fever Clinic 2 weeks before because of influenza A infection as evidenced by a weakly positive nucleic acid test result. Subsequently, the patient underwent isolated medical observation before his family was diagnosed with COVID-19. During the medical observation, the nucleic acid test presented weakly positive for influenza A again, and CT showed diffuse ground-glass opacities in both lungs. A deep learning (DL)-based computer-aided diagnostic system for pneumonia, which was trained with CT scans of patients with COVID-19, suggested this patient to have pneumonia, with the lesion volume accounting for 13.3% of the whole lungs (Fig. 1). Later, throat swab specimens from the patient were tested with rRT-PCR for SARS-CoV-2. After two consecutive negative results, a third SARS-CoV-2 rRT-PCR test confirmed the infection.

Case 2
A 36-year-old man presented with fever for 5 days (peak body temperature: 40℃) and was admitted to the Fever Clinic of the Beijing Haidian Hospital. The patient had no direct contact history with patients with COVID-19 or people from the Hubei province, but a recent travel history to Chongqing was reported. Physical examination showed fever with a body temperature of 38.5℃. Respiratory symptoms at admission included dry throat and difficulty breathing; no cough, sputum, or stuffy/runny nose was observed. Other symptoms included nausea, vomiting, and diarrhea. Laboratory examination revealed increased leukocyte (13.69 × 109/L) and neutrophil (10.42 × 109/L) counts, decreased differential count of lymphocytes (12.6%), and an elevated C-reactive protein level (155 mg/mL).
Chest CT showed emphysema in both upper lungs and diffuse ground-glass opacities in the right lower lobe, highly suggestive of viral pneumonia. In addition, the DL-based computer-aided diagnostic system also indicated a high risk of pneumonia with the infected area accounting for 8.9% of the whole lungs (Fig. 2). Subsequently, throat swab specimens were promptly collected for SARS-CoV-2 rRT-PCR. A negative result for SARS-CoV-2 was observed in the first rRT-PCR test. A second consecutive SARS-CoV-2 rRT-PCR test was conducted immediately thereafter, and a positive result was obtained. The patient was further confirmed with COVID-19 with additional positive rRT-PCR tests.