Inclusion Criteria:  Is between the ages of 18 and 36 months at the time of Screening visit 1 Has a legally acceptable representative capable of understanding the informed consent document and providing consent on the participant's behalf IgE-mediated allergy to 2 of peanut, almond, cashew, hazelnut or walnut, confirmed by:  Nut 1 pre-screening:  For at least one of almond, cashew, hazelnut or walnut (Nut 1)*:  History of ingestion with IgE-mediated reaction (birth to present) AND History of SPT ≥3mm OR History of sIgE ≥0.35 number of kilounits per liter (KuL) AND  Nut 2 pre-screening:  For a second nut out of peanut, almond, cashew, hazelnut or walnut (Nut 2):  History of SPT ≥3mm OR History sIgE ≥0.35 KuL  In clinic screening: Participants meeting pre-screening criteria for Nuts 1 and 2 above will be invited for in-clinic screening  SPT: wheal size ≥3mm at Visit 1 for 2 of peanut, almond, cashew, hazelnut or walnut AND OFC: react to ≤3000 mg protein top dose (4449 mg cumulative) in open, single nut OFC for 2 of peanut, almond, cashew, hazelnut or walnut  OFC not needed if:  History of failed OFC within past 3 months (confirmed by investigator review of discharge summary) OR History of anaphylaxis after ingestion within past 3 months based on investigator judgement +/- review of ER/Ambulance/medical notes  *Peanut is not included as Nut 1 to reduce the incidence of screening children with a peanut allergy only - children with peanut allergy may have been advised to avoid all other nuts. We require children to have eaten and reacted to at least one tree nut, and then the 2nd nut, which children may or may not have eaten, can be peanut or a tree nut.  Exclusion Criteria:  History of severe anaphylaxis (as defined by persistent hypotension, collapse, loss of consciousness, persistent hypoxia or ever needing more than 2 doses of intramuscular adrenaline or an intravenous adrenaline infusion for management of an allergic reaction) Severe anaphylaxis at study screening OFC (defined as persistent hypotension, collapse, loss of consciousness, persistent hypoxia, or requiring more than 2 doses of intramuscular adrenaline or an intravenous adrenaline infusion for management of an allergic reaction) Fails either screening OFC on dose 1 (0.5 mg). Underlying medical conditions that increase the risks associated with anaphylaxis (e.g., cardiac disease or poorly controlled asthma (defined below)) Confirmed eosinophilic esophagitis (EoE) or history indicating EoE Current use of beta-blockers or angiotensin-converting enzyme (ACE) inhibitors Receiving systemic immunomodulatory treatment Not commenced or unable to eat solid food Weight <7.5kgs (recommended minimum weight for EpiPen Jr (adrenaline autoinjector)) Has a sibling in the study  Defining uncontrolled asthma (Global Initiative for Asthma. Asthma management and prevention for adults and children older than 5 years)  In the past 4 weeks, has the patient had:  Daytime symptoms more than twice/week? Any night waking due to asthma? Short Acting Beta Agonist (SABA) reliever needed more than twice/week? Any activity limitation due to asthma? Uncontrolled - answered yes to 3-4 of these