An experimental vaccine is promising to prevent hay fever symptoms for at least two years, and this is after just six injections.
The new six week allergy treatment is a significant improvement over conventional treatment as it appears to offer long-term relief from the miseries of hay fever instead of injections once or twice a week over three to five years.
Researchers say that the technique may be applied to other substances that spark allergic reactions.
Peter Creticos of the Johns Hopkins Asthma and Allergy Center in Baltimore, and leader of the team, says they are looking at allergies to grass, dust mites and cats.
Creticos says they are not just treating the symptoms, but are targeting the fundamental defects in the immune system that cause allergies.
There are thought to be 40 million hay fever sufferers in the United States, and as many as 30 million are allergic to ragweed, a yellow flowering weed which is found east of the Rocky Mountains and plays havoc with hay fever sufferers in the autumn season.
The Creticos study involved 25 volunteers who experienced ragweed allergic problems each fall and were subjected to a treatment mix of a component of ragweed that sets off the allergic reaction with a synthetic chunk of DNA that stimulates the immune system, or a placebo.
In the study the 14 who received the treatment, known as AIC, had fewer hay-fever symptoms, used less allergy medication and reported a better quality of life than volunteers who received six dummy shots.
AIC is a DNA-based vaccine that blocks the action of IgE antibodies, which are involved in generating an allergic response, and IL-4, which plays a role in causing inflammation in nasal tissues.
The study participants were then monitored for two hay fever seasons and it was found that the vaccine group had a 60-percent reduction in allergy symptoms, including sneezing, runny nose, watery eyes and itching, compared to the placebo group.
There also appeared to be no no drop-off in the protective effect in the second year of the study.
The company has already started a phase 3 trial of the vaccine and expects to file for approval with the Food and Drug Administration in 2008.
The findings are published in the New England Journal of Medicine.