A retrospective analysis of children with mild and asymptomatic Omicron infections under 14: A single-center study

Omicron BA.5 subvariant has been proven to be more transmissible than other Omicron subvariants. But the studies on the spread of the Omicron BA.5 subvariant in children are still limited. This study aimed to analyze the clinical features of children infected with Omicron BA.5.2 variant in the mobile cabin hospital and the influence factors of the infections. Children with mild and asymptomatic Omicron infections under 14 years old who were admitted to the mobile cabin hospital from October 30 to December 7, 2022 were retrospectively collected. A total of 741 children, 424 boys (57.2%) and 317 girls (42.8%) were enrolled, including 145 asymptomatic cases (22.7%) and 493 (77.3%) mild cases. Upper respiratory tract infection was the dominant manifestation. Fever was the most common presenting symptom (80.7%), followed by cough (52.5%). The average time to symptom disappearance was 3.76 days, and the average negative conversion time of nucleic acid was 12.3 days. Univariate analysis showed that the negative conversion time of nucleic acid differed significantly across the age groups. The multivariate analysis showed that the older the age, the longer the negative conversion time of nucleic acid. Among those with the negative conversion time of nucleic acid longer than 12 days, age was positively correlated to the negative conversion time of nucleic acid, while the number of vaccine doses received was negatively correlated to the negative conversion time of nucleic acid. Omicron infection occurred in children of any age group, with good prospect for recovery. Age and number of vaccine doses received were risk factors influencing the negative conversion time of nucleic acid.