Detection of airborne respiratory viruses in paediatric patient rooms in Guangzhou, China

Background Transmission through contact/touch and respiratory droplets is well-established for the spread of certain respiratory viruses. Direct comparisons between respiratory viruses on the contribution of airborne virus-laden particles to transmission are limited. Methods Air sampling was conducted in five-bed paediatric patient rooms in a tertiary hospital in Guangzhou, China, from December 2017 through January 2020. Using National Institute for Occupational Safety and Health two-stage cyclone samplers, we collected air continuously for 4 h and quantified respiratory virus RNA/DNA by reverse transcriptase polymerase chain reaction. Results We conducted air sampling on 44 occasions and identified 24, 18, 16, 4 and 8 occasions that had ≥1 patient in the room tested positive for respiratory syncytial virus (RSV), adenovirus (AdV), parainfluenza virus (PIV) and influenza B or A virus, respectively. Influenza A virus was detected most frequently (72% of occasions), even in the absence of known infected patients. Influenza B virus, AdV and RSV were detected at low to moderate frequencies (12–50%), and PIV was rarely detected (8%). Viral loads ranged from 10 3 to 10 5 copies/m 3 , with influenza A virus showing the highest mean viral load of 8358 copies/m 3 (95% confidence interval [CI]: 6368–10,969), 4658 copies/m 3 (95% CI: 2337–9285) for influenza B virus, 6013 copies/m 3 (95% CI: 2360–15,323) for AdV, 1851 copies/m 3 (95% CI: 0–5.36∗10 13 ) for PIV and 970 copies/m 3 (95% CI: 486–1937) for RSV. Conclusions Healthcare workers and visitors are likely to be exposed to respiratory viruses in the air, even in the absence of known patients in close proximity. Our findings support universal infection control measures in healthcare settings, including increased respiratory virus surveillance in patients, improved indoor ventilation and reduced crowding.