I realize this is a fairly new game, but a handful of friends and I were playing last night and got to the first level where you can get "infested" by the parasite head-crab aliens.
The game prompts you to heal to counter it, and even on normal difficulty our Medic was going through 2 group heal beacons each time just to prevent death. I feel like either we're missing something or this is just a rather annoying game mechanic that feels a tad overtuned at the moment.
Note that our medic did not have the medic gun, as we weren't high enough level to unlock it yet.