Between 2002 and 2003, severe acute respiratory syndrome (SARS) infected over 8,000 people worldwide, with almost 800 deaths. As a result of this severe and highly contagious virus, researchers almost immediately started working on developing a vaccine. United States-based researchers took a portion of the SARS DNA to create the vaccine. In particular, they took the DNA of a protein that is responsible for penetrating healthy cells in humans, which causes infection. The DNA in the vaccine cannot actually cause SARS because it only contains the protein responsible for the transmission of the virus. When injected with the SARS vaccine, the body identifies this protein and attacks it. As a result, the body develops immunity to the SARS virus. Due to exposure of the virus in vaccine form, the immune system can destroy the virus in the event of infection [source: BBC News].
In 2004, U.S. researchers successfully gave a SARS vaccine to mice in a trial. The researchers later exposed these mice to the actual SARS vaccine; they found that these mice had very few virus particles in their lungs compared to mice who never received the SARS vaccine. This type of vaccine is much safer than other vaccines that are commonly used, as it uses DNA, rather than killed forms of the actual virus, such as in the conventional flu vaccine.
In China, in 2004, researchers successfully vaccinated people with the SARS vaccine. They found that there were very few side effects associated with the SARS vaccine. Researchers claim that an effective and approved SARS vaccine takes three to five years to produce. There is hope, therefore, that if there is another SARS outbreak in the future, the world will be well-equipped with an effective vaccine [source: SciDevNet].