Start with this review article in 1989, allergy shots for hay fever are well studied and quiet effective. https://sci-hub.se/https://www.tandfonline.com/doi/ab

Start with this review article in 1989, allergy shots for hay fever are well studied and quiet effective. https://sci-hub.se/https://www.tandfonline.com/doi/abs/10.1080/00325481.1989.11700701?journalCode=ipgm20 https://sci-hub.se/https://www.tandfonline.com/doi/abs/10.10... "Success rate is 20-50% or something like that" Effectiveness of allergy shots is generally related to the maximum dose you work up to. Allergy shots are expensive, and I had to get them for years to make my dust allergy manageable. Question you should be asking is how much of the low efficacy rate is due to early termination of treatment. "risk that the body develops other allergies for some reason." More plausible mechanism is that people who get allergy shots also get more thorough allergy testing, and discover new allergies they already had. What mechanism would result in new allergy development from small, controlled subcutanous allergen exposure, that would not manifest from continual daily seasonable exposure?