Jack Jumper ant (JJA) venom allergy is a uniquely Australian medical condition. It is the leading cause of venom allergy and affects up to three per cent of the population. 70 percent of people with JJA allergy will have another reaction on a repeat sting and this sensitivity appears to persist for many years. Venom immunotherapy (VIT) has been shown to be a safe and effective treatment in the prevention of severe systemic allergic reactions (anaphylaxis) to future stings. It is currently offered to patients as standard care in Tasmania, South Australia and Victoria. However, whilst JJA VIT has been used for many years, there is a lack of evidence on the long-term benefit of the treatment and how it impacts patient quality of life. This trial will offer patients who have completed a JJA VIT program (between 3 and \< 6-years duration) and have been off-treatment for at least 18-months and \< 5 years, to have a supervised JJA sting challenge and blood test to assess their JJA venom tolerance level. It will also ask them to complete a set of questionnaires at different timepoints to obtain a history of their exposure and reactions to JJA stings outside of the hospital setting (field stings), and to measure the impact of the completed VIT and knowledge of their sting challenge outcome on their quality of life and their behaviours around auto-injectors. These measures will be used to explore the long-term effectiveness of JJA VIT and the impact of a sting challenge post VIT on a patient's quality of life.