The National Institutes of Health is launching a human trial to test the safety of an experimental vaccine against severe acute respiratory syndrome.

SARS, which was first recognized in 2002, killed 774 people worldwide before being brought under control by quarantine, patient isolation and travel restrictions.

Since then, researchers have been studying the virus in an effort to develop a vaccine.

The National Institute of Allergy and Infectious Diseases said Monday it will test the vaccine in 10 volunteers, doing periodic follow-up exams for 32 weeks.

The vaccine has worked well in animals and this trial is primarily intended to determine if it is safe in people and to see if the volunteers produce antibodies, the institute said.

Unlike most vaccines, which use either a weakened or killed virus to spur the body to produce an immune reaction, this vaccine uses a small piece of DNA that encodes a viral protein. The researchers expect the DNA will direct human cells to produce proteins very similar to the SARS protein, and the immune system should recognize these proteins as foreign and then mount a defense against them.

While developing new vaccines can take decades, this trial gets under way less than two years after the disease was first recognized.

The NIAID vaccine is the second to begin being tested against SARS. Chinese researchers began human testing of a vaccine in May using an inactivated SARS virus.