A clinical trial in children presenting to hospital with an asthma attack, to compare the effectiveness of giving the additional treatment of anti-immunoglobulin E antibody or nothing on the time until their next asthma attack.

INTERVENTION: anti‐IgE antibody, omalizumab. The dose of omalizumab to be administered to each subject will be calculated using the subject’s baseline total serum or plasma IgE levels (IU/ml) plus the subject’s weight (kg) in accordance with the dosing table (described in the Xolair (Registered Trademark) (Omalizumab) Product Information Sheet). The Product Information Sheet is listed under Xolair (Registered Trademark) on the the Health Care Professionals page in the following website https://www.novartis.com.au/products/healthcare‐professionals The dose will be given as a subcutaneous (SC) injection. A single dose of omalizumab will be given. However, in accordance with the dosing table, each participant with sufficient body weight (kg) and total IgE levels to require a second dose of Omalizumab, will need their second dose of either Omalizumab or placebo to be given two weeks later. The treatment drug, omalizumab, (or placebo) will be administered at least 12 hours after the patient presents to hospital, at the enrolment visit. Treatment will be given in the hospital, so adherence will be monitored by the person administering the treatment CONDITION: asthma exacerbations PRIMARY OUTCOME: Time (number of days) to next asthma exacerbation in the subsequent six months ; This will be assessed by the review of medical records and diary records completed by the parents. SECONDARY OUTCOME: Amount (number of doses) of short‐acting beta2 agonists required in the first 6, 12 and 24 hours after treatment with omalizumab ; This will be assessed by the review of medical records. ; ; Amount (number) of asthma exacerbations in subsequent 12 months ; This will be assessed by the review of medical records and diary records completed by the parents as well as telephone interview at 12 months post recruitment. ; Amount (number) of asthma exacerbations in subsequent 6 months ; This will be assessed by the review of medical records and diary records completed by the parents. ; Time (number of days or hours) to discharge ; This will be assessed by the review of medical records. ; ; ; ; Time (number of days) respiratory symptoms persist after asthma exacerbation ; This will be assessed by the review of diary records completed by the parents. INCLUSION CRITERIA: 1. Male or female children 6‐12 years of age presenting to PMH ED with a diagnosis of either acute asthma or asthma exacerbation by the treating physician. 2. An acute asthma severity score of moderate or severe as defined by Qureshi, F. et al. NEJM (1998) 339:1030‐5. 3. Admission to hospital with acute wheeze or asthma at least once in the previous year. 4. Parent(s) or legal guardian(s) of the child is able to understand the study requirements and willing to provide informed consent