Typically, patients must go through a build-up phase of immunotherapy that might require 2 to 3 injections weekly for a period of 6 months. These injections must be given in a physician s office and patients must wait 30 minutes after each injection in the unlikely event they have a systemic reaction to immunotherapy. Once the build-up phase is complete, maintenance injections are given weekly to monthly. After three to five seasons of symptom relief, the treatment may be discontinued. Efficacy is usually sustained for several years after cessation of grass, tree and ragweed immunotherapy.
Relapses occur when immunotherapy is discontinued.
A good response to restarting such therapy occurs more rapidly than during the initial course of immunotherapy.