Vaccines for herpesviruses are not easy to make because the virus can evade the immune system by laying dormant in nerves, among other things. It's just a tough family of viruses to pin down. There's a phase 1 EBV vaccine [1] but it'll be a while before we see progress.
It's weird how unimaginative this field seems from a distance.
What is stopping modern medicine from engineering a competitive virus/bacteria/fungi that lurks about nerve bundles, attacks the herpes virus, and self-deprecates itself after.
Whoever come up with the idea of "God", a grand genius master architect, clearly had no understanding of how unbelievably shitty the engineering of living organisms is. I really cannot emphasize enough how poorly designed our bodies are. A physical manifestation of uncommented, heavily obfuscated, spaghetti code that's only viewable and editable in binary. And every "program" (human) is different and unique.
Yes, living things are amazing, but any designer approaching even basic levels competence factors in repairability and serviceability.
So all that is to say: It's crazy complex and any single thing is liable to have myriad first order, second order, third order...30th order negative effects.
Here's what stopping modern medicine from doing that:
1) we don't know how to make what you describe
2) if we did, we don't know if it would be safe to put in humans
3) the consequences getting this wrong could be very severe
4) getting such a thing approved would be nearly impossible because we have no idea how to evaluate something like this.
It's not from lack of imagination- even if you solved the technical difficulties (which are copious), there would still be huge regulatory burdens to overcome (which are even harder to overcome than medical research).
With that said, we've already done similar things with lentivirus, https://en.wikipedia.org/wiki/Lentiviral_vector_in_gene_ther... but one side effect is cancer, another being complex immune system reactions. Lentivirus are useful because they can invade non-dividing cells, for example nerve cells aren't dividing, which means most viruses won't target them.
I worked in this field for a few decades but it was all wasted time. Nobody is going to support you working on a research project like this.
I'm unaware of ANY viral infections having any upsides, possibly excepting whatever's native to our gut microbiome. And herpesviruses are very complicated to fight against.
If the downsides outweigh the upsides, why aren't we just eliminating them, as we have done for more deadly viruses like smallpox and polio?