The findings in this memo are based on rapid searches in the PubMed database. One researcher went through all search records, selected and summarised the findings. In the current situation, there is an urgent need for identifying the most important evidence quickly. Hence, we opted for this rapid approach despite an inherent risk of overlooking key evidence or making misguided judgements.
Three overviews and 14 primary studies were identified from the literature search and by manual searches in reference lists.
The included studies show that transmission can mainly be traced back to direct or indirect physical contact, but caution must be shown when using certain aerosol-generating procedures in hospitals. One study detected virus-containing particles from the air in patient rooms with hospitalised MERS-CoV patients, while another study did not find virus-containing particles in air samples taken 10 cm from the chin of a patient with ongoing SARS-CoV-2 infection. Both studies conducting air testing are subjected to methodological uncertainty.