23andMe are offering a free Health+Ancestry DNA test kit to people that meet the following criteria:
See here for more details and to apply:
https://you.23andme.com/covid19-study/
"The goal of the study is to understand genetic differences which may explain why symptoms of the illness range from very mild to very severe and help empower the scientific and medical communities to address this public health crisis."
"So far, preliminary results suggest that people with O blood types are between 9-18% less likely than individuals with other blood types to have tested positive for COVID-19."