I think that’s probably due to the nature of the fungal infection. It appears to take over the entire body, replacing human flesh with its own substance. Normal vulnerabilities don’t seem to apply, but it makes sense that since Cordyceps is using the host’s brain to control it, a headshot would take the Infected down.Can rabies victims survive multiple gunshots to the center of their mass and only be killed by a direct headshot? Because we see that multiple times in this show.