Medicare does not cover. Per Medicare NCD Manual:
110.9 - Antigens Prepared for Sublingual Administration
(Rev. 1, 10-03-03)
CIM 45-28
For antigens provided to patients on or after November 17, 1996, Medicare does not cover such antigens if they are to be administered sublingually, i.e., by placing drops under the patient’s tongue. This kind of allergy therapy has not been proven to be safe and effective. Antigens are covered only if they are administered by injection.