It’s Not Just the Shot

Vaccines spur the body to create its own medicine

OKLAHOMA CITY, October 12, 2009 – Lines, lines everywhere. Parents and kids, patiently (and impatiently) waiting. But it’s not the hot new video game system they want—it’s the flu shot.

Though many people dutifully roll up their sleeve for their annual flu vaccine, and this year millions will follow suit with the H1N1 vaccine, few know what that shot really accomplishes.

“Vaccines are not medicine, in the strictest sense of the word,” said Oklahoma Medical Research Foundation physician-scientist Judith James, M.D., Ph.D. “Vaccines are actually filled with a dead or weakened virus or bacteria, which prompt your body to make its own medicine.”

When the vaccine is injected or inhaled in a spray form, components of the viruses or bacteria, also called antigens, make their way into the body. The immune system goes on high alert, dispatching white blood cells, called B cells, to identify the intruders and figure out how to defeat them.

The B cells devise plans for creating proteins called antibodies that will kill the virus or bacteria and check in with T helper cells, which act as supervisors, making sure that the antibodies won’t harm the body. Once the plans are approved, the B cell starts pumping out antibodies, making a surplus that can be used if you come into contact with the virus or bacteria again.

So the protection the flu shot gives you results not from the vaccine itself but from your body’s natural disease-fighter, the immune system. But if you get the vaccine once, doesn’t your immune system know to watch for the flu virus forever? Why get a flu shot every year if you’ve already been vaccinated?

“The reason we get a new flu shot annually is because the strain of influenza that causes seasonal outbreaks is always changing,” said James, who holds the Lou C. Kerr Endowed Chair in Biomedical Research at OMRF. “Viruses, like the flu, are more likely to change over time, so we need new vaccines to get the body ready to fight them. Because bacteria, like tetanus, are much more stable, tetanus shots are needed less often.”

Although vaccines aren’t cures, they have prevented plenty of major illnesses. Before the advent of vaccines, smallpox killed millions worldwide. Vaccines for polio and rubella have also prevented paralysis and birth defects for thousands.

“Vaccines don’t work for everybody, and that’s part of what I research at OMRF,” said James. “Still, they are the best way we know to prevent several deadly diseases, which is why scientists are always working to create new and better vaccines.”

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