ABSTRACT
BACKGROUND: COVID-19 is a global pandemic. Currently, the predominant strain is SARS-CoV-2 Omicron subvariant BA.2 in many countries. Understanding its infection characteristics can facilitate clinical management. OBJECTIVES: This study aimed to characterize the clinical, laboratory, and high-resolution computed tomography (HRCT) findings in patients with mild or moderate infection from SARS-CoV-2 Omicron subvariant BA.2. METHODS: We performed a retrospective study on patients infected with SARS-CoV-2 Omicron subvariant BA.2 between April 4th and April 17th, 2022. The clinical characteristics, laboratory features, and HRCT images were reviewed. RESULTS: A total of 805 patients were included (411 males and 394 females, median age 33 years old). The infection was mild, moderate, severe, and asymptomatic in 490 (60.9%), 37 (4.6%), 0 (0.0%), and 278 (34.5%) patients, respectively. Notably, 186 (23.1%), 96 (11.9%), 265 (32.9%), 11 (3.4%), 7 (0.9%), and 398 (49.4%) patients had fever, cough, throat discomfort, stuffy or runny nose, fatigue, and no complaint, respectively. Furthermore, 162 (20.1%), 332 (41.2%), and 289 (35.9%) patients had decreased white blood cell counts, reduced lymphocytes, and elevated C-reactive protein levels, respectively. HRCT revealed pneumonia in 53 (6.6%) patients. The majority of the lung involvements were ground-glass opacity (50, 94.3%) mostly in the subpleural area. The grade of lung injury was mainly mild (90.6%). Short-term follow-ups showed that most patients with pneumonia recovered. CONCLUSION: Most patients with mild or moderate infection from SARS-CoV-2 Omicron subvariant BA.2 were adults, with fever and upper respiratory symptoms as the main clinical presentations. Lower respiratory infection was mild, with ground-glass opacity in the subpleural area as the main finding.