Seattle-based biotech company HDT Bio closed a seed round totaling roughly $3 million to support work on its COVID-19 vaccine candidate HDT-301.

Researchers from HDT Bio and the University of Washington in July published a rapid-release paper in the journal Science Translational Medicine reporting on promising early results from the vaccine as tested in mice and non-human primates.

HDT Bio’s team includes scientists focused in earlier phases of research, and the new funding will allow them to add staff who have experience in clinical disease trials, according to the company.

HDT-301 is a cutting-edge, replicating RNA vaccine. In this approach to preventing illness, the vaccine contains a string of RNA from the virus, which cells turn into protein, triggering an immune response. In traditional vaccines, the targeted virus or pathogen is inactivated and then injected into the body.

The vaccine includes