New SARS Vaccine in Trial

A new vaccine developed against severe acute respiratory syndrome (SARS) is now in a trial conducted by the Vaccine Research Center, U.S. National Institute of Allergy and Infectious Diseases (NIAID, Bethesda, MD, USA).

The vaccine was developed by researchers at the Vaccine Research Center, established five years ago. The primary goal of the trial is to determine if the experimental vaccine is safe in people, and it will be tested in 10 healthy volunteers. A secondary goal is to assess how well the vaccine stimulates the immune system to produce antibodies and cellular immunity.

Instead of being based on a weakened or inactivated virus, which is typical for vaccine development, the new vaccine is composed of a small circular piece of DNA that encodes the viral spike protein that protrudes from the outer envelope of the virus and helps it bind to cells it infects. Scientists modified the DNA to minimize the risk of it combining with the SARS virus or other coronaviruses. They expect that the DNA will direct human cells to produce proteins very similar to the SARS spike protein. The immune system should recognize these as foreign and then mount a defense against them. The vaccine has performed very well in mice.

"Two years ago, we didn't know that this virus existed,” noted Gary J. Nabel, M.D., director of the Vaccine Research Center. "Today, we begin clinical trials of a promising vaccine candidate. We owe the speed of this research to modern molecular genetics.”