Is there any evidence for influenza vaccination in children with asthma?

A 12 year old boy presents for a routine asthma follow-up appointment during the autumn. He takes 200 μg per day of inhaled budesonide and uses his salbutamol 3–4 times per week. His mother asks if the flu vaccine will make it less likely that he will have an asthma exacerbation over the winter. In children with asthma [patient] does influenza vaccination [intervention] reduce the number of asthma exacerbations associated with influenza [outcome]