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

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.

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.

Between January 2018 and December 2021, children were confirmed to have a PIV3 infection via throat swabs or nasopharyngeal aspirates. Some digital clinical data were analyzed, including demographic, epidemiological, diagnostic, and laboratory data.

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 patients with M. pneumoniae co-infection was found in girls (2 = 19.233, P < 0.001). Co-infections with M. pneumoniae were observed principally in patients aged 1 – 2 years (2 = 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 (2 = 16.424, P = 0.001) and co-infections with more than two pathogens (2 = 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 significantly 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.

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.