Modeling COVID Impacts

Early in the pandemic, in spring of 2020, a lot of my non-public health friends and family asked me what I thought of travel restrictions, pulling kids out of school, stay at home orders, and various government policies being inacted to control transmission. At the time, epidemiologic models were just coming online with model estimates of how bad the pandemic would be, but few actually were modeling the scenarios that real people were actually asking me about. I refered a lot of families and friends to statements made by CDC and other public health authorities.

But, I felt very uncomfortable recommending the advice of others without looking into the data and attempting to model some of the coronavirus transmission characteristics myself. So I developed some model scenarios and fit the models to actual early WA state data on infections at the time to help guide my own responses to these questions:

  • What does it mean to “flatten the curve”?
  • What is the impact of isolating sick people on reducing transmission?
  • Why was the timing of social distancing policies important?
  • Why travel limits may actually spread out the timing of the pandemic?
  • Why differences in implementation of control policies in different regions is counter-productive in reducing transmission?
  • What is herd immunity, and what level is required to theoretically no longer sustain transmission?

You can find interactive versions of my models, and the model results for these different questions, along with some brief descriptions of the implications of the model findings here:

It’s now a year later, and I haven’t gone back to do more modeling. But, in retrospect, I wish I had done more to model variations in community responses, like access to testing, and I guess now, access to vaccines, as equity seems to be a recurring theme in the the challenges of dealing this pandemic. I’ll post on some of the other work we’ve done since my earlier model scenarios that are more focused on understanding the impacts of COVID on communities in WA, and some of the equity issues.