I think the astronauts health makes them much less likely to die from Corona than 0.3% but exposing the current crew of the IIS does not sound like a good idea either.

Fatality rate is one thing, but being in a small space can cause high concentrations of virus and any health complication in space is a big deal.

A catastrophic failure is definitely a risk, but not sure how its magnitude should diminish our caution when it comes to bringing the virus to the space station (by your calc, it lowers the risk only by 5%).