Thank you for your recent inquiry.
I am afraid there is no definite answer to your question. The best we can do is quote you the statements from the most recent Parameters on insect hypersensitivity. As you can see from this quote, this is a decision that is entirely left to the clinical judgment of the physician administering immunotherapy. The decision is based upon factors such as the severity of the initial anaphylactic event, the difficulty the patient would have with continuing the shots, et cetera.
I wish I could give you a more direct answer, but based upon available evidence to date, there is none. Therefore physician judgment after assessing the above factors is all that we can offer you.
Thank you again for your inquiry and we hope this response is helpful to you.
"There are no specific tests to distinguish which patients will relapse after stopping VIT, but there is a higher risk in some patients than others. Relapse is less likely with 5 years than with 3 years of VIT.50,53 Although most patients can safely discontinue immunotherapy after this period of time, some patients with a history of severe anaphylaxis with shock or loss of consciousness still might be at continued risk for a systemic reaction if VIT is stopped, even after 5 years of immunotherapy.46,47,52 For this reason, some experts recommend an extended duration of immunotherapy, possibly indefinitely, in such patients. Other criteria suggested for stopping VIT include a decrease in serum venom-specific IgE to insignificant levels or conversion to a negative skin test response.54 Some patients have relapsed despite negative venom skin test responses. Repeat skin (or venomspecific IgE serum) testing is not required for consideration of discontinuing VIT. Measurements of venom-specific IgG antibodies have no predictive value when discontinuing VIT. The decision on stopping VIT requires a context-sensitive flexibility based on the available evidence.
The optimal duration of fire ant immunotherapy is less well defined. Most allergists consider stopping fire ant immunotherapy after a specified period (usually 3-5 years) eitherempirically or only when skin test or in vitro test results become negative.55 Until further data are available, a definitive recommendation about the duration of immunotherapy for fire ant sting allergy cannot be made."
Stinging insect hypersensitivity: A practice parameter update 2011. Golden DB, Moffitt J, Nicklas RA, Freeman T, Graft DF, Reisman RE, et al. J Allergy Clin Immunol. 2011 Apr;127(4):852-4 e23.
Phil Lieberman, M.D.