The binding energy difference doesn't indicate how it will play out in the real world. Viruses replicate exponentially, not linearly. Assuming that 21% difference in binding energy translates 1:1 to the scale of replication, it's a fucking massive difference. Assuming the same initial viral load, 21% is the the difference between a mild cold and dying on a respirator. Assuming baseline viral doubling over interval X 1 2 4 8 16 32 64 128 256 512 1024 2048 With 21% higher binding affinity/replication rate 1 2.42 5.8564 14.172488 34.29742096 82.9997587232 200.859416110144 486.07978698654848 1176.313084507447322 2846.677664508022518 6888.959948109414494 16671.283074424783076 8x the viral load after 11 cycles. There's far less time for the immune system to mount a response before it's overwhelmed.