The Armored Infected are Blighters in Police Riot Armor. They act like average Blighters but are harder to kill. They wear Body Armor on every inch of their bodies except their arms, but putting into account that they require headshots like all Blighters, this isn't a big problem. The main problem is that they wear Bullet-Proof Helmets. Their Helmets are a quite tough obstacle in killing them. It can take around several shots or whacks with a pistol or cricket bat to pop off their Helmets. But once their Helmets are gone, they are just like average Blighters.
Armored Infected can only bite the player once their helmet comes off, regardless of if they are wearing their helmets, they are immune to fire damage such as from molotovs, though they can be easily killed by grenades.