Immunotherapy Benefits Last After Shots Stop
Effects of Allergy Shots May Persist for More Than 5 Years
March 23, 2005 -- allergies at bay long after the shots stop, according to a new study.
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Researchers found people who had immunotherapy, which consists of repeated shots containing low levels of allergy-causing substances (allergens), were still reaping the benefits up to 12 years later.
Previous studies have shown that people who received allergy shots against grass pollen were still free of hay fever symptoms, such as runny nose and watery eyes, for at least three years after it was discontinued. But this study shows that immunotherapy may provide benefits more than five years after the allergy shots stop.
Effects May Last 12 Years
In the study, researchers compared the allergy symptoms reported by a group of allergy patients who received immunotherapy one to four years ago with those reported by a group of allergy patients who stopped getting allergy shots five to 12 years ago.
In the first group, the average allergy symptom score before immunotherapy was 8.48, and it dropped to 2.96 immediately after the allergy shots stopped. After an average of more than two and a half years later, the average allergy symptom score was still less than half (3.97) than it was before immunotherapy.
But researchers found the same level of allergy relief in the second group nearly eight years after the allergy shots stopped as they found in the first group.
In the second group, the average allergy symptoms score dropped from 8.26 to 2.94 after immunotherapy and climbed only to 3.95 after an average of seven and a half years.
They say the results indicate the benefits of immunotherapy do not diminish over time.
Researchers presented the study this week at the annual meeting of the American Academy of Allergy, Asthma, and Immunology in San Antonio.