Infection Vials are one-use items that will infect one random body part of the user.
To get an infection vial, a player must have a naniteCollection effect of at least 2. With that, once the player defeats a feral, his/her Research proficiency is then used to make a check of whether or not he/she gets a bubbling infection vial. The higher the Research, the higher the chance of getting one.
Vials usually have levels to them. A player cannot use a vial that is 6 or more levels above their own. For instance, if a player is level 16, they can drink vials that are level 21 and under.