The COVIDOSE project will estimate the number of SARS-CoV-2 virus particles it takes to infect a human with the Covid-19 disease, and compare this to occurrences of virus in the environment.

Infectious dose for a viral disease is the number of viruses that needs to enter your body in order to make you sick. This dose varies a lot between different pathogens, and with what route it entered the body. We will estimate this for the coronavirus SARS-COV2 in humans, and use this knowledge to develop environmental risk models.

Combining the genetic variability of individual viruses sequenced from many different patients with total virus variability and mutation rate to use coalescence models to estimate how many viruses initially started the infection in each patient. A patient may of course have been initially exposed to a far larger dose of viruses than necessary to make him or her sick, but not a smaller one.

In collaboration with other projects, we will analyze virus samples from contaminated air and different surfaces and see how these relate to the infectious dose to make risk models and better models of spread, which will inform epidemiological studies, choice of protective equipment and procedures for medical personnel and the general public. Communication is designed to follow an open-science model.

Project manager

Kyrre Kausrud, NVI

Ryan Easterday, UiO


  • The Institute of Public Health (FHI)
  • University of Nottingham
  • University of Oslo (UiO
  • Vestre Viken Helseforetak (VVHF)
Funded by the Research Council of Norway
Research Areas
Bioinformatics, Epidemiology, Risk assesment