The findings in this memo are based on rapid PubMed searches. 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.
We identified six eligible reviews and 15 eligible primary studies. Eligible studies were summarised in text and tables.
Available evidence suggests that SARS-CoV-2, SARS-CoV and MERS-CoV can survive on inanimate surfaces for hours or days. Less is known about the virulence of virus deposited on inanimate surfaces.
Available evidence shows that SARS-CoV-2 tends to transmit between closely related individuals. Indirect transmission through inanimate surfaces (fomites) may also occur, but as available studies are performed in a laboratory or hospital setting it remains unclear to what extent contaminated surfaces constitutes a risk transmission in a community setting. A mathematical modelling study suggests that the relative contribution of environmental transmission in a community setting is considerably lower than direct contact, but these results are very uncertain.
It is very challenging to acquire strong evidence regarding the relative importance of different routes of transmission. People in close relations and people staying in close proximity to each other are exposed to multiple ways of transmission. General infection prevention measures will also affect multiple routes of transmission.