Earlier this year, the Centers for Disease Control and Prevention released the results of their most recent National Immunization Survey. According to the report, not enough adults are getting shots that can prevent serious illnesses. For example, only 2.1 percent of adults 18 to 64 are immunized against diphtheria, whooping cough (pertussis) and tetanus—three diseases that are preventable with a simple DPT vaccine.

Believed by many to be an uncomfortable task only for children to endure, some immunizations, such as DPT, necessitate a “booster” shot every five or ten years into adulthood.

“A vaccine is essentially a dead or less active form of an infectious agent that is injected into the body to stimulate the production of antibodies from your immune system,” explains John L. Brodhead Jr., M.D., associate professor of internal medicine at the Keck School of Medicine of USC. “The immunization activate the antibodies to fight infection if necessary, but eventually, these antibodies may die off. If they die off, you are no longer immune to the infectious agent, such as tetanus, which is why the booster shots are important.”

Not every immunization needs a booster, says Brodhead. Talk to your doctor about which vaccines may be right for you. The danger of skipping out on shots, however, is that you may not be protected against disease, he points out.

“Many adults have a false sense of security thinking that if they got shots as a kid, they’re covered,” says Brodhead.

If you are unsure of your vaccination history, he says that your doctor can test for antibodies of particular viruses. If the antibody count is low or borderline, then you can receive a booster.

In addition to booster shots, some new vaccines have been developed that are specific to the adult population, such as zostavax, for the shingles virus. Others, like flu vaccinations, change each year. There are an average of 36,000 deaths related to flu each year, many of which could be prevented by immunization, according to the CDC.

“Adults should get immunized unless there is a contraindication, for example, an allergy to a component of the vaccine,” says Brodhead. He notes that a primary care physician should always be consulted before getting any immunization. For some diseases, only specific groups need to get immunized, he says.

Here are Brodhead’s recommendations for adult vaccinations, including the specific populations who should receive them:

Tetanus: Everyone should get a booster shot every 10 years. People who suffer puncture wounds or deep skin abrasions usually are given boosters automatically when they go in for emergency room treatment.

Rubella (German measles): Health care workers and women of childbearing age should get vaccinations.

Hepatitis A: People at high risk, including intravenous drug users, men who have sex with men, institutionalized people and people traveling to or living in areas where it is endemic, should get vaccinations.

Hepatitis B and C: High-risk adults, dialysis patients and health care workers should get a hepatitis B vaccination and should get tested for hepatitis C because it often exhibits no symptoms for years. There is not yet a vaccination for hepatitis C. Both of these diseases are transmitted through sexual contact, needle sharing or exposure to blood products.

Pneumonia: Vaccinations are recommended for people over 65, plus diabetics and people who have had their spleens removed or suffer chronic heart, lung or liver disease.

Influenza: Annual flu shots are recommended for the same group of people that should get pneumonia vaccinations, plus health care workers.

Travelers: People planning to visit foreign countries should contact those countries’ embassies or consulates to ask if specific vaccinations are recommended or required. The Centers for Disease Control and Prevention also can recommend what shots international travelers should get. Visit CDC's website for information.

Zostavax: This is a vaccination against Herpes zoster, also known as shingles. This painful skin condition is a result of reactivation of the chicken pox virus, which can stay latent in the body for years and years. In a small percentage of shingles patients, postherpetic neuralgia—nerve damage that may cause severe pain—can occur. Anyone who experienced chicken pox as a child and is aged 60 or over should receive the zostavax vaccine. This vaccine is not for children, women who are pregnant or may become pregnant, or individuals with a weakened immune system.

For more information on vaccinations, visit the CDC’s Web site. The site includes a quiz that can help you figure out which vaccinations to talk to your doctor about here.