Allergy shots (immunotherapy) promise long-lasting relief from seasonal sniffles and other symptoms. But they’re time-consuming, involving weekly injections for at least three months and monthly maintenance shots for three to five years. And total treatment costs are typically thousands of dollars, though insurance usually covers at least part of the expense.

Are the shots worth the trouble? Yes, if allergy medicine does not control your symptoms. A January 2007 review from the Cochrane Collaboration, an international research organization, analyzed data from 51 clinical studies involving almost 2,900 patients. The conclusion: The shots reduced hay-fever symptoms and medication use with a low risk of serious side effects. And the protection can last many years, studies show. Shots might also help prevent the development of new allergies or even asthma.

CR’s take. If drug treatments haven’t helped, ask your physician to recommend an allergist, or find one by going to the Web site of the American College of Allergy, Asthma and Immunology (www.acaai.org/locateallergist). Wait at your allergist’s office for half an hour after each shot so that he or she can treat you quickly if you’re one of the rare patients who have a bad reaction.