More Detailed Answer:
The materials technology that makes body armor ballistically resistant does not necessarily make it stab or puncture resistant (and vice versa). The IACP/DuPont KEVLAR Survivors Club. has documented a number of incidents over the years where ballistic resistant armor has provided some protection against attacks from a variety of sharp edged and other weapons. However, one should not presume that a ballistic resistant vest will protect against non-ballistic threats, or that a stab resistant vest provides ballistic protection. Armor that complies with NIJ Standards will clearly identify the types and level of threats that they are designed to protect against.