increased exposure to daycare or large families, but none are well supported enough to be recommended for this indication. Early pet exposure may be useful. Results from exposure to pets at other times are inconclusive and it is only recommended that pets be removed from the home if a person has allergic symptoms to said pet. Dietary restrictions during pregnancy or when breast feeding have not been found to be effective at preventing asthma in children and are not recommended. Omega-3 consumption, mediterranean diet and anti-oxidants have been suggested by some studies that might help preventing crisis but the evidence is still inconclusive. Reducing or eliminating compounds known to sensitive people from the work place may be effective. It is not clear if annual influenza vaccinations affects the risk of exacerbations. Immunization, however, is recommended by the World Health Organization. Smoking bans are effective in decreasing exacerbations of asthma. Management While there is no cure for asthma, symptoms can typically be improved. The most effective treatment for asthma is identifying triggers, such as cigarette smoke, pets or other allergens, and eliminating exposure to them. If trigger avoidance is insufficient, the use of medication is recommended. Pharmaceutical drugs are selected based on, among other things, the severity of illness and the frequency of symptoms. Specific medications for asthma are broadly classified into fast-acting and long-acting categories. The medications listed below have demonstrated efficacy in improving asthma symptoms, however "real world" use-effectiveness is limited as around half of people with asthma worldwide remain sub-optimally controlled, even when treated. People with asthma may remain sub-optimally controlled either because optimum doses of asthma medications do not work (called "refractory" asthma) or because individuals are either unable (e.g. inability to afford treatment, poor inhaler technique) or unwilling (e.g., wish to avoid side effects of corticosteroids) to take optimum doses of prescribed asthma medications (called "difficult to treat" asthma). In practice, it is not possible to distinguish "refractory" from "difficult to treat" categories for patients who have never taken optimum doses of asthma medications. A related issue is that the asthma efficacy trials upon which the pharmacological treatment guidelines are based have systematically excluded the majority of people with asthma. For example, asthma efficacy treatment trials always exclude otherwise eligible people who smoke, and smoking blunts the efficacy of inhaled corticosteroids, the mainstay of asthma control management. Bronchodilators are recommended for short-term relief of symptoms. In