Parainfluenza Virus Type 3 Co-infection with Other Respiratory Pathogens Among Hospitalized Children with Acute Respiratory Infections in Wuhan, China

Background: Bacterial and viral co-infections are increasingly recognized as the cause of Acute Respiratory Infection (ARI). The role of co-infection in ARI patients with Parainfluenza Virus type 3 (PIV3) infection is unclear.Objectives: This study aimed to determine the prevalence of PIV3 co-infections in hospitalized children and assess the co-infections' role in ARI patients with PIV3 infections.Methods: Between January 2018 and December 2021, children were confirmed to have a PIV3 infection via throat swabs or nasopha-ryngeal aspirates. Some digital clinical data were analyzed, including demographic, epidemiological, diagnostic, and laboratory data. Results: During the study period from 2018 to 2021, 2,539 patients were hospitalized with ARI caused by PIV3. Of them, 34.0% had co-infection with other pathogens, and 2.4% had co-infection with more than two pathogens. Mycoplasma pneumoniae was the most common co-infecting pathogen (71.3%), followed by other bacteria (13.3%) and viruses (8.2%). A significantly higher proportion of pa-tients with M. pneumoniae co-infection was found in girls (x2 =19.233, P < 0.001). Co-infections with M. pneumoniae were observed principally in patients aged 1 - 2 years (x2 = 202.130, P < 0.001). In contrast, viral (56.3%) and bacterial (66.1%) co-infections occurred mainly in children younger than one year. The diagnosis of PIV3 as a single infection included pneumonia (41.2%), bronchitis (39.9%), upper respiratory tract infections (15.0%), and laryngitis (3.9%), which were distinguished from those with bacterial co-infections (x2 =16.424, P = 0.001) and co-infections with more than two pathogens (x2 =11.687, P = 0.010). Co-infections of PIV3 with any pathogen were not associated with admissions to intensive care units or ventilator support. However, the mean hospitalization was signifi-cantly higher in M. pneumoniae co-infections (t = 2.367, P = 0.018), bacterial co-infections (t = 2.402, P = 0.016), and co-infections with more than two pathogens (t = 2.827, P = 0.006) than in single PIV3 infection. Conclusions: Parainfluenza virus type 3 frequently occurs with other pathogens. The epidemiological and clinical characteristics of co-infections with different pathogens differed. Mycoplasma pneumoniae co-infections, bacterial co-infections, and co-infections with more than two pathogens lengthened the hospitalization. Bacterial co-infections and co-infections with more than two pathogens increased the severity of ARI and worsened the symptoms.

Automated summary

This study investigated the prevalence of co-infections in hospitalized children with Parainfluenza Virus type 3 (PIV3) infection and their role in Acute Respiratory Infection (ARI). The results showed that 34.0% of PIV3 infections had co-infection with other pathogens, with Mycoplasma pneumoniae being the most common co-infecting pathogen. Co-infections with Mycoplasma pneumoniae were more common in girls and in patients aged 1-2 years, while viral and bacterial co-infections occurred mainly in children younger than one year. Co-infections with Mycoplasma pneumoniae, bacterial co-infections, and co-infections with more than two pathogens prolonged hospitalization.