# Analysis of influenza A, influenza B and Mycoplasma pneumoniae infection in children hospitalized with acute respiratory tract infection in Xi’an from 2021 to 2023

## TL;DR

This study analyzed the presence of three pathogens in children hospitalized with respiratory infections in Xi’an from 2021 to 2023, finding significant changes in infection rates over time.

## Contribution

The study provides updated epidemiological data on FluA, FluB, and Mp infections in children with ARTI in Xi’an over a three-year period.

## Key findings

- Mycoplasma pneumoniae was the most frequently detected pathogen, with a detection rate of 30.14%.
- FluA detection increased significantly from 0.53% in 2021 to 12.90% in 2023.
- Co-infection rates rose from 0.75% in 2021 to 2.38% in 2023.

## Abstract

To evaluate the occurrence of three pathogens, influenza virus A (FluA), influenza virus B (FluB) and Mycoplasma pneumoniae (Mp) in children hospitalized with acute respiratory tract infection (ARTI) between 2021 and 2023.

FluA, FluB and Mp were detected by antigen/antibody kit in specimens from 29,014 children with ARTI admitted to Xi’an Children’s Hospital.

The total pathogen detection rate was 43.79% (12,707/29014) with 30.14% (8,745/29014) Mp-positive cases, 7.08% (55/29014) FluA-positive and 6.57% (1907/29014) FluB-positive. Total detection rates were 28.05% (2,472/8813) in 2021, 29.38% (2,550/8680) in 2022 and 66.70% (7,685/11521) in 2023. Co-infection rates with two or more pathogens increased over the period of interest from 0.75% (66/8813) in 2021, 0.93% (81/8680) in 2022 to 2.38% (274/11521) in 2023 (χ2 = 115.931, p < 0.001). FluA detection also increased and was present in 0.53% cases in 2021, 6.01% in 2022 and 12.90% in 2023, reaching a peak in February 2023 of 17.83% and March 2023 of 64.42%. FluB detection rates were more stable at 5.25% in 2021, 7.67% in 2022 and 6.75% in 2023, reaching a peak of 22.17% in December 2023. Mp detection was higher in 2023 at 47.05% with a peak of 82.21% in October 2023 than in 2021 (15.89%) or 2022 (15.69%). More FluA-positive cases were seen in the >12 age groups than in younger children and FluB detection also increased with age. Mp infection was detected in the >4 age group.

The pathogen spectrum and epidemiology of ARTI changed between 2021 and 2023. Age-specific bandings of infection were seen in the cohort of children. Outbreaks of FluA, FluB and Mp influence the pathology of ARTI.