Most people think immunization is just for kids. But National Immunization Awareness Month, which is celebrated in August, underscores the importance of vaccination for people of all ages. After all, the old adage that says “an ounce of prevention is worth a pound of cure” holds true throughout life.

The term immunization refers to the action of making people resistant (immune) to certain infectious diseases, many of which can be very serious or even deadly. Immunization is typically accomplished through inoculation with vaccines.

If you’re like me, you probably received a series of vaccines when you were a child. Over the years, the schedule of vaccines given to children and teens has evolved as doctors have learned more about various infectious diseases and new and improved vaccines become available.

For the current guidelines from the US Centers for Disease Control and Prevention, see Recommended Child and Adolescent Immunization Scheduled for Ages 18 and Younger.  And here, the American Academy of Family Physicians describes the recommended vaccines in greater detail: Childhood Vaccines: What They Are and Why Your Child Needs Them.

Most vaccines are made using a weakened version of the infectious germs, such as bacteria or viruses, that cause the disease, or materials that resemble those germs. Vaccines work by prompting your body’s own defense against disease, your immune system, to produce infection-fighting cells to attack the invading germs.

To better understand how vaccines work, let’s take a closer look at how the immune system fights infection.

When germs invade your body for the first time, your immune system uses certain white blood cells to destroy them. Special white cells called macrophages consume and digest the germs. B-lymphocytes produce disease-fighting antibodies that attack the germs, and T-lymphocytes attack cells in the body that have already been infected by the bacteria or virus.

Once antibodies are created in response to an initial infection, your body keeps them and uses them to fight future infections with the same germ. That’s how vaccines provide protection for the long haul. Many vaccines protect you for years, some for most of your life. But sometimes, a vaccine loses its effectiveness over time. In that case, you may require a “booster” later in life.

Adults need boosters of certain vaccines they received as children, such as the Tdap, which is the vaccine for tetanus, diphtheria and pertussis (whooping cough), and the vaccine against hepatitis B. People of all ages should get a tetanus booster every 10 years. A booster is recommended any time you’re exposed to the tetanus toxin as well.

It is also recommended that adults receive vaccines for diseases such as influenza, pneumococcal pneumonia and shingles. Here’s a rundown of the recommended vaccines for adults. In addition, vaccination against diseases that are common in other countries is recommended before you travel outside the US. Here’s more information about vaccines for travelers.

Immunization is important for two reasons: It protects you from disease, and it protects the people around you. How vaccines protect you has already been explored, but how do vaccines protect your community?

If a large number of people in a community are vaccinated and immune to a disease, the germs that cause it can’t spread from person to person as easily. Spreading germs this way can make the people around you sick and lead to an all-out outbreak of the disease. The protection that results from community-wide vaccination is called herd immunity.

There are some people who don’t get vaccinated because they fear side effects. Most vaccines cause only miner side effects such as a mild fever or soreness at the site of the injection. And there is no credible evidence that vaccination leads to autism, as some people suggest.

All in all, immunization is a safe and effective way to protect against many serious, possibly deadly, infectious diseases. Thanks to immunization, diseases such as polio and smallpox are near obliteration in this country.

Keeping Americans safe from those diseases and many others is why spreading the word about immunization is a priority of National Immunization Awareness Month.