It actually works in a very similar fashion. Both vaccines and allergy drops change the immune system and create antibodies. In the case of vaccines, your body

It actually works in a very similar fashion. Both vaccines and allergy drops change the immune system and create antibodies. In the case of vaccines, your body creates antibodies that bind to the virus to prevent them from causing symptoms of the virus (sickness/illness). For allergy shots/drops your body also makes antibodies to bind to the allergens and prevent them from causing symptoms of the allergens like sneezing or nasal congestion. So both work in a similar mechanism. The challenge with allergy drops and allergy shots is the clinical data shows that it takes a much longer time for your body to create an immune system change that decreases your allergy symptoms than it does for your body to create antibodies to block a virus. Does this make sense?