BACKGROUND: Researchers have been working on a DNA-based vaccine for the flu for several years. While not yet ready for widespread use, if there were a global outbreak of the potentially deadly virus, such a vaccine could be fast-tracked into use. The Center for Disease Control estimates that more than 200,000 people in the U.S. are hospitalized each year as a result of the flu, and more than 30,000 die from it. Globally, the flu kills close to half a million people every year.
HOW VACCINES WORK: There are three basic strains of the flu virus: A, B and C. A is the most common strain, and the most severe. The flu vaccine works by triggering the body's immune system response. The body recognizes the vaccine as a foreign invader and produces antibodies to it. However, flu strains differ from year to year; that's why there is a different vaccine each year.
Currently, flu vaccines are made by incubating the three strains of the flu virus expected to strike in a given year are injected into millions of chicken eggs to multiply before being extracted and packaged. It is a labor-intensive and time-consuming technique that is much the same as when it was first invented in the 18th century.
WHAT ARE DNA VACCINES?: DNA vaccines are a form of gene therapy in which just a few genes are extracted from the virus and injected into people. Unlike the standard process, which takes up to six months, DNA-based vaccines could be ready in less than three months. The downside is they have never been tested in full-blown clinical trials.
WHAT IS THE FLU: The flu is caused by the influenza virus, which targets the respiratory tract by binding to the surface of cells. Then the virus releases its genetic information (RNA) into the cell's nucleus to replicate itself. When the cell dies, those copies are released into the body, infecting other cells. Flu symptoms are unpleasant, but not life-threatening by themselves. However, the flu weakens the immune system, making the body vulnerable to more serious infections, such as pneumonia.