That is what the v hull is for; it directs the blast outward. You would lose the tire, wheel, and possibly axle, and could get a mobility kill on the vehicle, but they train for that and go with multiple trucks (more if it is more dangerous; there were places with a six truck night minimum, which was scary for me in a single unarmored 1990s BMW sedan with a 9mm...). Other vehicles radio in, cover the downed truck, may ram/push it out of the way, or tow, or crossload. The big concerns are secondary ieds, triggered after the response begins (so people out of the vehicles), or a ground assault (uncommon, and rarely effective. One truck with a .50 up top can basically hold its own.)

Traumatic Brain Injury, concussion, etc from overpressure or being thrown around is possible, but everyone is wearing armor and helmets, and there is a lot of mass in the vehicle, so if you can get rid of most of the energy of an ied, and keep people from being pierced by anything, it is probably enough. The big risk in ieds is massive bleeding; enough that military first aid prioritizes bleeding control ("massive hemorrhage" in MARCH vs. ABC); usually this is from a limb being blown off, since the torso is well armored).