Household transmission risks can be especially high for respiratory viral diseases and have impactful economic and public health consequences. The study objective was to estimate influenza and rhinovirus infection risks for a child sharing a bedroom with another infected child using a computational fluid dynamics (CFD) quantitative microbial risk assessment (QMRA) approach. The scenario was two recumbent children lying on twin-sized beds in a 25.5 m3 bedroom for 6 h. The infected individual released virus-laden aerosols under scenarios: Low and high severity shedding. Rhinovirus and influenza A virus (H1N1 and H3N2) dose-response curves were used to estimate infection risks. Infection risks were highest for rhinovirus, >0.99 regardless of viral shedding intensity. High severity settings yielded risks 1.5 and 0.9 log10 higher for H3N2 and H1N1 infection risks, respectively. A plume formed from the infected individuals exhaled breath to the susceptible individual's face, which may explain, in part, the high risks estimated. While settings for tidal breathing did not disrupt the formation of this plume, increased air exchange rate did. Respiratory viral infection risks can be high in shared bedroom scenarios, especially with low fresh air ventilation and alignment of furniture such that plumes can form between the faces of individuals.
Pham et al. (2026) studied this question.