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expert reaction to systematic review on the effectiveness of air filtering and decontamination to prevent respiratory infections

A study published in Preventative Medicine looks at the effectiveness of air filtering to prevent respiratory infections. 


Dr Shaun Fitzgerald, Director, Centre for Climate Repair, University of Cambridge, said:

“These findings are important because they highlight the difficulty in answering the exam question ‘will the installation an air cleaning device reduce the likelihood of getting an infection?’ Although laboratory studies can be used to determine the effectiveness in reducing concentrations of particles in a given room, there are many other factors which need to be considered if we are ultimately interested in the potential impact on the likelihood of getting ill. There can be transmission routes beyond aerosols such as via surfaces or droplets emitted by an infector falling directly onto someone else. And study design is fraught with difficulties in the real world, especially so during emergency pandemics. Hence, the comments on confounding factors referred to in this study are important. The paucity and/or weakness of evidence of studies in the real-world was also highlighted in the systematic review of environmental controls during the Covid-19 pandemic published earlier this year. In that paper ( it was found that air cleaning devices may have a role in reducing transmission in certain settings. However, the evidence was usually of low or very low quality and certainty, and hence the level of confidence ascribed to the conclusion is low.”


Effectiveness of filtering or decontaminating air to reduce or prevent respiratory infections: A systematic review’ by Julii Brainard et al. was in Preventative Medicine at 00:01 UK time on Friday 17th November.


Declared interests

Dr Shaun Fitzgerald: Dr Shaun Fitzgerald is an author on the paper referenced in the comment. No other DOIs was received.

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