Transmission of SARS-CoV-2: implications for infection prevention precautions On 9 July 2020, WHO updated the scientific brief on the transmission of SARS-CoV-2, the virus that causes COVID-19. This replaces a previous version of the scientific brief, published on 29 March 2020. As the spread of the virus continues to intensify around the world, we are gaining more knowledge as to how and when the virus is able to spread between people. This is important in order to continuously ensure that the most effective measures to suppress transmission of the virus and prevent associated illness and death are used. Below, we provide the key points of the brief.