Comparative Analysis of Clinical Characteristics in Influenza B, Influenza A/H1N1, and A/H3N2 Infections and the Impact of Co-infection with Other Respiratory Pathogens

authors:

avatar Runyun Sun 1 , avatar Ying Cheng 2 , avatar Hongbo Hu ORCID 1 , *

Department of Clinical Laboratory, Maternal and Child Health Hospital of Hubei Province, China
Department of Pediatrics, Maternal and Child Health Hospital of Hubei Province, Wuhan, China
Jundishapur Journal of Microbiology: Vol.17, issue 7; e148636
published online: August 28, 2024
article type: Research Article
revised: August 03, 2024
DOI: https://doi.org/10.5812/jjm-148636

how to cite: Sun R, Cheng Y, Hu H. Comparative Analysis of Clinical Characteristics in Influenza B, Influenza A/H1N1, and A/H3N2 Infections and the Impact of Co-infection with Other Respiratory Pathogens. Jundishapur J Microbiol. 2024;17(7):e148636. https://doi.org/10.5812/jjm-148636.

Abstract

Background: In pediatric populations, influenza viruses such as Influenza B, Influenza A/H1N1, and Influenza A/H3N2 pose distinct challenges due to their unique clinical characteristics. Co-infections with other respiratory pathogens can lead to more severe disease progression in children, although the specific impacts of these co-infections are not yet fully understood. 
Objective: To comprehend the disparities in clinical characteristics among children with single infections of Influenza B, Influenza A/H1N1, and Influenza A/H3N2, and to evaluate the impact of mixed infection with other respiratory pathogens on the severity of the disease in children. 
Methods: A retrospective study assessed the severity of pediatric influenza hospitalizations during 2022-2023 by correlating virus types/subtypes with clinical outcomes, including pneumonia incidence, mechanical ventilation necessity, PICU admissions, and duration of hospital stay. 
Results: The study encompassed 1380 pediatric patients with influenza: 343 with Influenza A/H1N1, 678 with A/H3N2, and 359 with Influenza B. In those aged six and above, Influenza A/H3N2 infection resulted in higher pneumonia rates and longer hospital stays compared to Influenza A/H1N1 and B (p < 0.05). There were also laboratory result differences between single infections of Influenza A and B within the same age group. Influenza A H1N1's co-infection rate is 3.5%, notably lower than H3N2's 11.9% and Influenza B's 10.6% (p<0.05). Discrepancies in clinical manifestations between single and co-infections of Influenza A/H3N2 and B were observed, with co-infections exhibiting elevated pneumonia incidences and prolonged hospital stays compared to single infections (p < 0.05). 
Conclusions: In patients aged six and older, Influenza A/H3N2 is associated with higher pneumonia rates and longer hospital stays. Co-infections involving Influenza B or A/H3N2 and additional respiratory pathogens further increase pneumonia risk and extend the length of hospitalization.