MedImmune

(MEDI)

is working with the National Institutes of Health to develop a live intranasal vaccine meant to prevent the avian flu.

Researchers are hoping that a vaccine, which is beginning early human trials, could be as effective in preventing avian influenza as it is in defending against seasonal strains of other types of the flu.

Since the MedImmune vaccine would be delivered as a nasal spray, it's expected to spark a faster and broader immune response, according to the company. MedImmune already sells a spray called FluMist that uses a live version of the influenza virus to prevent infection by normal strains. Traditional flu shots contain a dead form of the virus that prompts the body to make antibodies.

"The initiation of this trial is the next step in MedImmune's ongoing commitment to ensure the nation is adequately protected against seasonal influenza and prepared for a potential influenza pandemic by using the latest in scientific and medical advancements," the company said in a press release Thursday.

The phase I avian flu trial, which is currently enrolling patients, is designed to evaluate the vaccine's safety and effectiveness at intercepting the H5N1 strain of the bird flu. The study will involve 20 healthy individuals between the ages of 18 and 49, MedImmune said.

"We believe that our influenza vaccine technology may provide several advantages over the flu shot that will be critically important in protecting people against a pandemic influenza virus," said Dr. James F. Young, MedImmune's president of research and development.

H5N1, which is transmitted through direct contact with infected poultry and bird feces, is believed to be responsible for more than 100 deaths, mostly in Asia. The disease has turned up in parts of Europe in recent months. So far, there is no indication that the infection can spread from human to human, but scientists believe that if a mutation occurs, a worldwide pandemic could ultimately result.

Normal seasonal flu usually causes mild respiratory symptoms, but avian flu is particularly aggressive and can lead to pneumonia, multiple organ failure or even death. More than half of those infected with the virus have died, and most cases have occurred in previously healthy children and young adults.

The Health and Human Services Department recently gave MedImmune, of Gaithersburg, Md., $170 million to expedite the development of its flu vaccine. The company plans to license its technology to the World Health Organization and other government agencies to develop flu vaccines.

Current government stockpiles of avian flu fighters include the antiviral drugs Tamiflu, developed by

Gilead

(GILD) - Get Report

and marketed by

Roche

, and Relenza, developed by

Biota

and sold by

GlaxoSmithKline's

(GSK) - Get Report

. These drugs would be administered in known cases of the avian flu, but no known effective preventative measures, such as a vaccine, are currently available.

MedImmune's shares were up 38 cents, or 1.3% to $29.53.