system
Given the following post, respond as if you're commenting on Reddit:
human
Why don’t we have vaccines for all Herpes Viruses?

Ok so I hope I don’t sound like a complete idiot, keep in mind I have very little medical knowledge. So we have vaccines for shingles and chicken pox, which are herpes viruses. However we don’t have a vaccine for Cold sores, Genital Herpes, or Mononucleosis (also a herpes virus). Why is this? I know they are obviously different mutations but they all stem from the same viral tree. Is this something that the medical community is working on or is it a lost cause to find an umbrella Herpes vaccine?
gpt
Vaccines work by training your immune system to respond to the pathogen. Herpes simplex virus 1 and 2 (the kinds that cause cold sores and genital sores) are immunoevasive, which means that they have a mechanism to avoid destruction by your immune system. As your immune system begins to respond to the virus, herpes will hide inside nearby nerves (but not destroy them like other tissue). Normally, virus-infected cells are detected by your immune system and destroyed by cytotoxic T cells, but your nerve cells have *immune privilege*, which means your immune system does not attack them. Herpes lies there in a dormant state until a biochemical stressor (high stress, hormonal changes associated with menstrual cycles, new medications, etc) cause them to pop back out and reinfect the nearby tissue. Also, since nerves don’t move around, this is why herpes almost always reappears in the same location. It just pops in and out of the same hidey hole.