February 1, 2006 Spraying viral genes directly through the skin is a new technique that turns infinitesimal amounts of DNA into an effective vaccine. If approved for use in humans, the new procedure could save lives in case of a flu pandemic, by skipping the current, time-consuming production of vaccines in chicken eggs.
LONDON--A new flu vaccine could save lives and protect us from a deadly outbreak. But can the United States handle a widespread flu epidemic? Most experts would agree -- not with the way we currently mass-produce the vaccine. It currently takes at least six months to a year to make flu vaccines, but that's soon to change.
We all know the signs; but what if a new, more-powerful, more-deadly strain of the flu emerges?
John Beadle, a researcher from the Infectious Disease and Oncology department at PowderMed, Ltd. in London, says, "The traditional way of making vaccines has a number of significant drawbacks."
The biggest drawback is the amount of time it takes to make, which is too long. This 1950's-style vaccine process using chicken eggs takes too long, putting lives at risk if an outbreak occurs. Now, a new vaccine based on flu virus DNA could be a faster way to fight the flu.
"DNA vaccines can be manufactured very rapidly, and they can be manufactured in large amounts," Dr. Beadle says.
Infectious disease researchers extract just a few genes from the DNA of the flu virus to make a vaccine. Then, microscopic particles are coated with the vaccine and shot into the body at super-fast speeds using this new, needle-free device. "It's because the DNA gets into the cells of the skin that it produces such a strong immune response," Dr. Beadle says.
A better response is important for older Americans, like 77-year old Claire Mobley. "Having had it once, I don't want to get it again."
This new, high technology could be the solution to an old problem -- producing a vaccine in half the time of traditional methods. Dr. Beadle says, "That means that a lot more lives can be saved within that period if we have a pandemic."
The new DNA vaccine and new administering device for influenza is not yet FDA approved. Human clinical trials are planned for this year to test it against the bird flu, but any mass-produced product is still several years away. A flu outbreak or worse -- a pandemic -- could speed up the FDA approval process and bring the vaccine closer to use.
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.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.