3.1 Clinical characteristics of pediatric inpatients with pneumonia prior to and during the COVID-19 pandemic
A total of 1038 children with pneumonia admitted to the Department of Pediatric Pulmonology of Xinhua Hospital were enrolled, including 825 cases occurred from March to August 2019 and 213 cases during the same period in 2020, which indicated a reduction of 74% in the number of pneumonia inpatients after the outbreak of the COVID-19 pandemic. Figure 1 depicts monthly distribution of these inpatients.
Clinical characteristics of the pneumonia inpatients prior to and during the COVID-19 pandemic were compared, as shown in Table 1. The median age of the patients in 2020 was much smaller than that in 2019 (P< 0.01), while the median hospital stay in 2020 was signifcantly longer than that in 2019 (P < 0.01). No differences were found in gender and season of hospitalization between the two years (P > 0.05).
For pathogens, both virus and MP infection rate were much lower during the COVID-19 pandemic than those prior to it (P < 0.01), whereas no significant difference was found in bacterial infection rate between the two years (P > 0.05). In virus infections, coxsackie virus was the most common, followed by IV, PIV and ADV in 2020, while IV was the most common virus, followed by PIV, ADV and coxsackie virus in 2019. Compared with 2019, the positive rates of RSV, ADV, IV and PIV were decreased in 2020. However, the positive rate of coxsackie virus was higher in 2020 than that in 2019. Mixed infections were signifcantly less frequent during the COVID-19 pandemic than those before the pandemic (P< 0.01). Co-infections with viruses and MP were the most common type of mixed infection in both 2019 and 2020.
Regarding allergens, compared with 2019, the positive rates of house dust mite, shrimp and crab were significantly higher in 2020 (P< 0.01). And for micronutrients, the levels of vitamin B2, B6, C and 25(OH)D in 2020 were observed to be significantly lower than those in 2019 (P < 0.05).