Vaccinations aren't just for children. Older adults need them, too, to ward off preventable infectious diseases, especially influenza and pneumonia. Yet many adults aren't following the recommended vaccination schedule.

In 2011, only 62% of Americans aged 65 years and older were vaccinated against pneumonia, just over 50% got a needed tetanus vaccine, and a mere 15% were vaccinated against shingles.

The August 2013 Harvard Women's Health Watch asked Dr. Elisa Choi, an internal medicine and infectious disease specialist at Harvard Vanguard Medical Center and faculty member at Harvard Medical School, to address five myths and misconceptions that may be keeping adults from getting the vaccinations they need.

Myth: I'll catch the flu from the influenza vaccine. Fact: The injectable flu vaccine is not a live vaccine, so it cannot, in any way, transmit the flu virus.

Myth: The flu vaccine isn't effective in older adults. Fact: Each year, the flu vaccine formulation is based on predictions of which strains are most likely to circulate in the coming flu season. Other strains may enter the mix. But even if you catch a flu virus that wasn't in the vaccination, the vaccine isn't useless. It could make the infection less severe.

Myth: Vaccines contain mercury, which could make me sick. Fact: According to the CDC, there is no evidence that the low doses of thimerosal, a mercury-containing preservative used in some vaccines, is harmful. If you're still concerned, you can ask your doctor for a thimerosal-free flu vaccine.

Myth: Vaccines overload the immune system.Fact: Considering that the immune system faces constant bombardment from microbes in the environment, the small amount of bacteria and viruses in one vaccination can barely be considered an assault. In fact, vaccines strengthen the immune system by arming it against infectious agents.

Myth: Older adults don't need to be vaccinated.Fact: The opposite is actually true. Among many older individuals, the immune system loses some of its ability to protect against infectious diseases even as they face an increasing number of chronic health conditions that can leave them more susceptible to infection.

Read the full-length article: "Vaccinations: Separating Myth From Reality"

Why are older adults so behind on their vaccinations?

"First and foremost, I think vaccinations are not always on the top of the list of what to discuss at an office visit, both for the patient and for the health care provider," says Dr. Choi. "I think there's also a lack of awareness about the need for vaccinations and how important they are," she adds