Australian scientists are also scrambling to determine whether this is a viable source of transmission after a cluster of cases was detected in a Brisbane managed isolation and quarantine (MIQ) facility. There appears to have been no close contact between the guests. So what do we know about spread through ventilation? How big is the risk? How Covid-19 spreads The two main ways Covid-19 spreads are: An individual inhales large infected droplets expelled by an infected person through, say, coughs or sneezes. An individual touches a contaminated surface covered in viral particles and transfers the virus into their system. It appears the virus can survive on some surfaces for up to 72 hours. The amount of time it survives depends on the temperature, humidity and UV light.