Comparison of prevalence and outcomes of SARS-CoV-2 infection between preterm and full-term children after lifting the prevention and control measures in China: a nationwide cross-sectional survey.

OBJECTIVES: To analyze whether there were differences in the prevalence and outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection between preterm-born and full-term children after lifting the prevention and control measures in China. METHODS: This survey was conducted in March 2023 after nation-wide lifting of the prevention and control measures for coronavirus disease 2019 (COVID-19) in China. Data were collected from parents of children < 8 years of age across the country through the "Wenjuanxing (Questionnaire Star)" platform. Differences between preterm-born and full-term children in binary outcomes were assessed by binary logistic regression or modified Poisson regression. Models were weighted using entropy balancing. RESULTS: A total of 1981 children with valid questionnaires were included in the analysis, comprising 544 preterm-born children (27.5%) and 1437 full-term children (72.5%). The difference in proportion of SARS-CoV-2 infections between preterm-born and full-term children (73.5% vs. 77.5%) was statistically non-significant. The infected preterm-born children exhibited more severe clinical presentations of SARS-CoV-2 infection relative to those born at full term (OR = 1.549, 95% CI: 1.025-2.342). Compared with full-term children, preterm-born children showed a prolonged hospital stay (OR = 2.472, 95% CI: 1.380-4.430) and a higher propensity for respiratory support (OR = 4.147, 95% CI: 1.336-12.868). Among infected preterm-born children, those with bronchopulmonary dysplasia (BPD) had a higher risk of severe SARS-CoV-2 infection than those without BPD (OR = 2.485, 95% CI: 1.340-4.610). However, the associations were attenuated and became statistically non-significant after accounting for gestational age. CONCLUSIONS: Preterm birth was associated with an increased severity of SARS-CoV-2 infection in children aged 8 years and younger. Moreover, having BPD was associated with a higher risk of severe SARS-CoV-2 illness among preterm children which may be partially explained by the lower gestational age.