Researchers at The Johns Hopkins University School of Medicine have successfully used an experimental DNA-based vaccine to protect against ragweed allergies, commonly known as hay fever, after just six injections. Patients receiving the vaccine showed an average 60 percent reduction in allergy symptoms compared to those receiving a placebo.
The experimental therapy holds the promise of one day eliminating the need for traditional allergy medicines targeting allergy symptoms, such as nasal steroids and antihistamines, and providing a safer, faster replacement for immunotherapy regimens, which are costly and take years to work, the researchers say.
The Hopkins study, conducted during two fall ragweed ("hay fever" ) seasons in Baltimore, Md., enrolled 25 volunteers, ages 23 to 60, with a demonstrated history of ragweed allergy. Fourteen people received the vaccine, administered as six weekly shots, while 11 others received placebo injections.
During the test period, allergic symptoms were monitored and recorded, right down to how often volunteers' noses ran and how many times they sneezed. Compared to the placebo group, those who received the vaccine exhibited a 60 percent reduction in all of their allergy symptoms, including sneezing, runny nose, watery eyes and itching.
Relief from allergic symptoms was as pronounced in the second year as in the first, even though no more vaccine was administered. Lead investigator Peter Creticos, M.D., medical director of the Johns Hopkins Asthma and Allergy Center in Baltimore, explained that such prolonged relief is an important part of his team's findings because it appears that the vaccine's efficacy doesn't wear off quickly. A new study, currently under way, will further examine the drug's lasting effects in a larger group of participants.
Creticos' current findings are published in the Oct. 5 issue of the New England Journal of Medicine.