Exhaled aerosols among PCR-confirmed SARS-CoV-2-infected children

Background: Data on aerosol emissions during spontaneous breathing among children are limited. We aimed to understand the role of children in the spread of SARS-CoV-2 and to assess whether aerosol measurements could help detect superspreaders (individuals with extremely high exhaled aerosol particle counts). Methods: In a prospective study, we measured exhaled aerosol particle concentrations and size distributions in PCR-positive and PCR-negative children/adolescents (2–17 years) using the Resp-Aer-Meter (Palas GmbH, Germany). Health status, medical history, vaccination, and prior infection were recorded. Particle counts were compared using linear regression models. Results: Among 250 participants (105 PCR-positive, 145 PCR-negative; median age 9 years, IQR 7–11; 49.6% female), 81.9% of PCR-positive participants were symptomatic. The overall median particle count was 79.55 particles/L. Older children tended to exhale more particles (1–5 years: 79.54 p/L; 6–11 years: 77.96 p/L; 12–17 years: 98.63 p/L). SARS-CoV-2 status was not a predictor in bivariate analysis (t = 0.82, p = 0.415) but was significant in a multiple regression controlling for age, BMI, vaccination, and prior infection (t ≈ 2.81, p = 0.005). COVID-19 vaccination status was a highly significant predictor of higher exhaled particle counts (p < 0.001). Particle size distributions differed between PCR-positive and PCR-negative groups (p = 0.041), with median size 0.21 µm in both, and a narrower distribution in PCR-positive participants; most particles were <0.5 µm. Conclusion: Children and adolescents with SARS-CoV-2 infection did not show elevated aerosol levels compared to uninfected peers, and no superspreaders were identified. Aerosol measurement is not suitable as a screening tool to interrupt transmission chains in this age group.

Thomas S Murray, Josue Sznitman, Richard Martinello, Pia Schuchmann, Gerhard Scheuch, Rolf Naumann, Marius Keute, Thomas Lücke, Stefan Zielen, Folke Brinkmann