Allergy Vaccine: 6-Shot Cure?
Study Shows Just 6 Weekly Vaccinations Gave Relief From Ragweed Allergy
Experimental Vaccine vs. Traditional Allergy Shots
Creticos and colleagues originally enrolled 25 people with ragweed allergy in their study. Half got the ragweed allergy vaccine -- one shot a week for six weeks, with gradually increasing amounts of ragweed allergen -- and half got fake injections.
Six shots sound like a lot -- unless you've ever taken allergy shots. These shots are simply tiny doses of whatever it is you are allergic to, given in weekly and then monthly doses over four or five years. The idea is to gradually train the immune system to tolerate the allergen. This treatment works. But it is very inconvenient and, while it's considered safe, still carries a risk of serious allergic reactions.
"Most people just can't deal with four or five years of shots -- and some stay on the treatment for six to 10 years," Creticos says. "The vaccine is a way to reach a markedly greater percentage of people whom we have not been able to reach due to fear of reactions."
Fifteen subjects, nine in the placebo group and six in the vaccine group, completed both years of the vaccine study.
Fewer Allergy Symptoms
After getting the shots, the patients who received the vaccine reported about 60% fewer allergy symptoms than those who got fake shots. At the peak of the second ragweed season, those who got the vaccine didn't need any antihistamines or decongestants.
"The results are very impressive in terms of the amount of relief of allergy symptoms patients got with just six injections, with no side effects -- and it lasted for two years," Broide says. "One needs to be realistic, however, and make sure this holds up in larger studies with more patients."
Creticos and colleagues currently are enrolling patients with ragweed-related asthmaasthma in a larger study. Eventually they hope to move to the kinds of clinical trial that lead to FDA approval.
"This is still several years into the future," Broide says. "Meanwhile, current immunotherapy is still very effective and safe. Patients should continue with their allergy injections."
While the current vaccine is formulated with ragweed allergen, Creticos says that it should work with other allergens. He expects that future studies will test vaccines against grass, dust mite, and cat allergiesallergies.