Viruses accrue small amounts of genetic variation over time. By sequencing the virus, we can see this variation and use it to understand where an individual virus likely came from and how it is moving through a population. This helps public health teams to estimate how many cases are due to local transmission as opposed to imported cases. In this proposal, we will establish ways to use virus sequences to understand transmission in a high-resolution way that is not possible with epidemiological or virus sequence data alone. To do this, we will combine viral sequences with epidemiological data in new ways, establishing high-resolution pictures of transmission. We will operationalize the use of these combined datasets for real-time COVID19 public health use in BC.