127 - Exhaled Aerosols in Children with Respiratory Tract Infections

Publication Number: 127.4779

Desiree Gutmann, Lucile Packard Children's Hospital Stanford, Palo Alto, CA, United States; Celine Neder, Goethe Universität Frankfurt am Main, Frankfurt am Main, Hessen, Germany; Dimitra Hamm Le Clément Kasfiki, Kinderarzt Praxis Hamm Le Clément Kasfikis Offenbach, Germany, Offenbach am Main, Hessen, Germany; Anton Landeis, Department for Children and Adolescents, University Hospital Frankfurt, Goethe University, Frankfurt, Germany, Regensburg, Bayern, Germany; Emily-Rose Ume, Klinik für Kinder- und Jugendmedizin Frankfurt, Frankfurt, Hessen, Germany; Martin Hutter, Department for Children and Adolescents, University Hospital Frankfurt, Goethe University, Frankfurt, Germany, Frankfurt, Hessen, Germany; Holger F.. Rabenau, University hospital Frankfurt, Frankfurt am Main, Hessen, Germany; Stefan Zielen, Medaimun GmbH, Frankfurt, Hessen, Germany

Background: Viral respiratory tract infections are primarily transmitted via droplets and aerosols. Previous research found an increased concentration of exhaled aerosols in children with SARS-CoV-2 infection. However, prior studies showed that severe symptoms in children with SARS-CoV-2 infection are rare, which might influence these findings. The pattern of exhaled aerosols in children and adolescents with other viral respiratory tract infections, that are known to cause more severe illnesses in children has not yet been well studied.

Objective: The aim of this study was to compare exhaled aerosols in children and adolescents with symptomatic respiratory tract infections caused by SARS-CoV-2 with other respiratory viruses (including influenza, human metapneumovirus (hMPV) and RSV). This will provide important information for future respiratory surges and mitigation strategies in the setting of viral transmission.

Design/Methods: This prospective, epidemiological study was conducted from December 2021 to March 2022. Included were 50 children and adolescents (aged 6-17 years) with SARS-CoV-2 negative respiratory tract infection. The cohort was compared to asymptomatic controls (n=91) and 40 SARS-CoV-2 positive children (delta variant n=22, omicron variant n=18). Patients were recruited in a pediatrics primary care practice in Offenbach, Germany, and at the pediatric urgent care facility of the University Hospital in Frankfurt, Germany. Viral testing was conducted with multiplex PCR. Aerosol measurements were conducted with the Resp-Aer-Meter.

Results: Viral testing with multiplex PCR was positive in 25 of 50 (50%) patients with acute respiratory tract infection. The most identified viruses were human rhinovirus (hRV; n=8), human metapneumovirus (hMPV; n=7), and influenza virus (n=4). In three patients, two viruses were detected (two with hMPV and hRV and one with Influenza A and Adenovirus). The median exhaled aerosol concentration in asymptomatic controls was 187 /L (5 – 937). A significantly increased exhaled aerosol concentration compared to the control group was found in all viral infections. In the cohort of SARS-CoV-2 negative viral infections, the median was 386 /L (18 – 16003; p=0.0001). In the SARS-CoV-2 delta variant positive group, the median was 418 /L (81 – 3982; p=0.0002), and in the SARS-CoV-2 omicron variant positive group, the median was 252 /L (45 – 1023; p=0.047).

Conclusion(s): Significantly elevated exhaled aerosol concentrations compared to healthy controls were found in children and adolescents viral respiratory tract infections with common childhood respiratory pathogens as well as SARS-CoV-2.

Table 1: Characteristics of the control, non-COVID viruses, and COVID groups
Table 1.pdfDisplayed are the main characteristics of the study groups. The COVID group is shown as a whole as well as sorted by variant (Delta and Omicron).

Exhaled particle counts in controls, non-COVID viruses, and COVID groups (delta and omicron)
Figure 1.pdfMedian and Range of exhaled particle counts in particles/L in control group, non-COVID viruses group, and COVID groups (delta variant and omicron variant) on a logarithmic scale.