Objective: To investigate the epidemiological characteristics of respiratory syncytial virus (RSV) in hospitalized children in Ningbo City, so as to provide insights into developing prevention and control strategies for RSV. Methods: Basic information, clinical data and throat swab samples were collected from hospitalized children with respiratory infection in Ningbo University Affiliated Women and Children's Hospital from July 2019 to December 2023. Multiple fluorescence PCR-capillary electrophoresis was employed to detect nucleic acids of 11 non-bacterial respiratory pathogens. RSV detection in hospitalized children by time, gender and age was descriptively analyzed. Results: A total of 49 449 throat swab samples of hospitalized children with respiratory infections were detected. There were 4 310 samples positive for RSV, with a detection rate of 8.72%. The detection of positive specimens peaked from November to February in 2019 and 2020, from August to October in 2021, and from May to September in 2023. The RSV detection rate in boys was higher than that in girls (9.25% vs. 8.04%, P<0.05). The detection rate of RSV was highest in the children under 1 year of age (16.37%). The RSV detection rate tended to decrease with age (P<0.05). Among the specimens with positive RSV detection, 3 407 were positive for RSV alone (79.05%), while 903 were detected as mixed infections (20.95%). The non-bacterial pathogens with higher percentages of mixed detection were human rhinovirus, Mycoplasma pneumoniae and human parainfluenza virus. Conclusion Atypical seasonal epidemic of RSV infections appeared in 2021 and 2023 among hospitalized children in Ningbo City, with high detection rates in boys and children under 1 year of age, and a certain percentage of mixed infections.

To analyze the infection and drug-resistant gene 23S rRNA mutations of mycoplasma pneumoniae (Mp) in hospitalized children aged 0-17 in Ningbo City from 2019 to 2023. Throat swabs were collected from hospitalized children with respiratory tract infections in Ningbo University Affiliated Women and Children′s Hospital from 2019 to 2023. They were subjected to real-time fluorescence quantitative polymerase chain reaction detection to analyze Mp infection and drug-resistant gene (23S rRNA) mutations. Intergroup comparisons were made by the Chi-square test or Fisher′s exact probability method. A total of 18 968 hospitalized children were included, with a total positive rate of 30.37% (5 760/18 968). The total positive rate of drug-resistant gene mutations was 82.45% (4 749/5 760). The positive rate of Mp in male children was 29.26%, which was lower than that in female children (31.67%, χ 2=12.948, P<0.001). The positive rate of Mp drug-resistant gene mutations in male children was 82.52%, which was higher than that in female children(82.37%, χ 2=0.021, P=0.885). The positive rates of Mp increased with age ( χ 2=1 722.21, P<0.001). The positive rates of Mp drug-resistant gene mutations also increased with age ( χ 2=13.152, P<0.001). In the four seasons, the total positive rate of Mp in summer and autumn was significantly higher than that in winter and spring ( χ 2=1 085.149, P<0.001). Among them, the Mp positive rates in the summer and autumn of 2019 were as high as 38.26% and 34.49%, while in the summer and autumn of 2020, the Mp positive rates were 2.55% and 1.65%, respectively, which were the lowest in previous years. In the summer and autumn of 2023, the Mp positive rates increased to 47.22% and 51.06%. There was no statistically significant difference in the detection rate of Mp drug-resistant gene mutations among the four seasons. In Conclusion, Mp infection was more prevalent in the summer and autumn in Ningbo city and females and children aged 7-17 were more susceptible. The epidemic of Mp infection in Ningbo occurred in the summer of 2019. After the COVID-19 pandemic in 2020, the positive rate of Mp rapidly decreased and later remained in a low incidence state. After the lifting of restrictive prevention and control measures in 2023, the Mp positive rate returned to an epidemic state. The positive rate of Mp drug-resistant gene (23S rRNA) mutations was relatively high.

To analyze the infection and drug-resistant gene 23S rRNA mutations of mycoplasma pneumoniae (Mp) in hospitalized children aged 0-17 in Ningbo City from 2019 to 2023. Throat swabs were collected from hospitalized children with respiratory tract infections in Ningbo University Affiliated Women and Children′s Hospital from 2019 to 2023. They were subjected to real-time fluorescence quantitative polymerase chain reaction detection to analyze Mp infection and drug-resistant gene (23S rRNA) mutations. Intergroup comparisons were made by the Chi-square test or Fisher′s exact probability method. A total of 18 968 hospitalized children were included, with a total positive rate of 30.37% (5 760/18 968). The total positive rate of drug-resistant gene mutations was 82.45% (4 749/5 760). The positive rate of Mp in male children was 29.26%, which was lower than that in female children (31.67%, χ 2=12.948, P<0.001). The positive rate of Mp drug-resistant gene mutations in male children was 82.52%, which was higher than that in female children(82.37%, χ 2=0.021, P=0.885). The positive rates of Mp increased with age ( χ 2=1 722.21, P<0.001). The positive rates of Mp drug-resistant gene mutations also increased with age ( χ 2=13.152, P<0.001). In the four seasons, the total positive rate of Mp in summer and autumn was significantly higher than that in winter and spring ( χ 2=1 085.149, P<0.001). Among them, the Mp positive rates in the summer and autumn of 2019 were as high as 38.26% and 34.49%, while in the summer and autumn of 2020, the Mp positive rates were 2.55% and 1.65%, respectively, which were the lowest in previous years. In the summer and autumn of 2023, the Mp positive rates increased to 47.22% and 51.06%. There was no statistically significant difference in the detection rate of Mp drug-resistant gene mutations among the four seasons. In Conclusion, Mp infection was more prevalent in the summer and autumn in Ningbo city and females and children aged 7-17 were more susceptible. The epidemic of Mp infection in Ningbo occurred in the summer of 2019. After the COVID-19 pandemic in 2020, the positive rate of Mp rapidly decreased and later remained in a low incidence state. After the lifting of restrictive prevention and control measures in 2023, the Mp positive rate returned to an epidemic state. The positive rate of Mp drug-resistant gene (23S rRNA) mutations was relatively high.