I think you have illuminated the crux of the non-existent issue At 97% reduction, even a virus with extraordinary replication speed is significantly hindered. The replication would need to be 1/(1-0.97)=33.33 fold to negate Brilacidin. I'm not sure the transport mechanisms available can even expose enough cells to support replication anywhere near that, otherwise the lethality would be crazy fast and it's not.
When mathematics and data are used in prediction we call this an 'educated guess'.
So, for those that might think I am daydreaming at $800 IPIX, please at least agree to call it 'educated daydreaming'.