COVIDOSE: Determining infectious dose for SARS-CoV-2 and assessing contact/proximity risk

The main goal of the COVIDOSE project is to estimate the infectious dose of the coronavirus SARS-COV2 that causes COVID-19, and use this to develop risk models for getting sick from coming into contact with the virus in different ways. The infectious dose for a pathogen (virus, bacteria, fungus, etc.) is the number of individual bacteria / viruses that must enter your body to make you sick. This dose varies by many orders of magnitude between different pathogens, and may also vary with the route by which it entered the body. However, having an infectious dose is very useful for designing practical security measures, as it lets you know how effective, time consuming and expensive they need to be - and how sensitive the controls - need to be. It also allows you to calculate the risk accumulated by coming into contact with several small doses of the pathogen and so on. To estimate the infectious dose for SARS-CoV-2 in humans, we will isolate and sequence thousands of individual virus particles from individual patients. We find variance between the genomes of the individual virus particles in the form of mutations. However, these mutations occur over time at a fairly regular rate, so large genomic datasets will allow us to calculate the rate at which these mutations occur. This is called a molecular clock. By combining the genetic variability between patients and within individual patients with this molecular clock, we can estimate how large a population of viruses first started the infection in each patient. We collaborate with other Research Council of Norway projects at FHI and FFI to study contagion and development between connected cases of covid-19. This will allow us to create models and estimates of becoming infected that will inform epidemiological studies.