As an adult, do you skip vaccines because you don’t think you still need them? Many of us aren’t getting the protection we need, according to infectious-disease experts.

“Each year, at least 30,000 people die from complications related to vaccine-preventable diseases,” says Marvin M. Lipman, M.D., Consumer Reports’ chief medical adviser. “Getting the right shots doesn’t guarantee that you won’t get sick, but it will significantly improve your odds.”

Here, answers to four common questions about adult vaccines.

I was fully vaccinated as a child. Why do I need more vaccines now?

Over time you may lose the ability to fend off diseases you were vaccinated against earlier. Some adult vaccines are boosters, building your immunity against those illnesses. Others protect against diseases that are more common in adulthood.

According to the Centers for Disease Control and Prevention (CDC), all adults should have an annual flu shot; a Td booster every 10 years to ward off tetanus and diphtheria; a zoster vaccine at age 60 to guard against shingles; and a pneumococcal vaccine at age 65 to protect against a type of pneumonia.

“If you’re unsure if your shots are up to date, it’s best to get vaccinated,” Lipman says. “It’s better to get revaccinated than go without protection.”

Are vaccines less effective for me now that I’m older?

Probably. Vaccines work by tricking the immune system into producing disease-fighting proteins called antibodies.

“Older people don’t form antibodies as well as younger people, so the older you are, the less effective that vaccine is going to be,” Lipman explains.

But even if adult vaccines you get are only 50 percent effective in preventing disease, he says, “you will likely have a milder case if you do get sick.” That’s important because as we age, illnesses can hit harder and lead to more complications

Every time I have a flu shot I feel lousy afterward. Is the shot giving me the flu??

A flu shot might cause mild side effects such as a sore arm, redness, and swelling at the injection site, and even a slight fever, but it’s unlikely that any vaccine will really make you sick.

“To put to rest an old myth,” says William Schaffner, M.D., a professor at the Vanderbilt University School of Medicine and consultant to the CDC’s Advisory Committee on Immunization Practices, “you cannot get flu from the flu vaccine.”

If you do get sick after being vaccinated, it’s probably a coincidence, Schaffner says. Most flu shots are given from September to December, to prepare you for peak flu season in the winter and early spring.

Once in a while, though, a vaccine does cause serious side effects. For example, according to the CDC, about one in a million people develops Guillain-Barré syndrome after a flu shot. That can cause temporary muscle weakness and tingling, breathing difficulties, and in rare cases, permanent paralysis. But a large 2013 study found that the flu itself is linked to a higher risk of Guillain-Barré syndrome than the vaccine.

Do I really need a shingles vaccine. If so, when?

If you're 60 or older, and haven't had the vaccine that protects against shingles, it's smart to do so (unless you have a medical reason not to get the shot).

A shingles infection, which occurs when a dormant chickenpox virus “wakes up,” can cause a burning, stinging rash and nerve pain (postherpetic neuralgia, or PHN) that can linger long after the rash subsides.

The vaccine cuts shingles risk by half and the odds of PHN by almost 70 percent.

Why age 60?  Although some people do come down with shingles earlier, the risk starts to rise significantly at that age and beyond. And the one-time shot begins to lose effectiveness after five years.

“It looks like the shingles vaccine is like a pistol with one bullet,” Schaffner says. “Do you fire it at 40 or 50? We shoot it at 60 because that will give you the most protection when you’re at the greatest risk of the disease.”

Editor's Note: This article also appeared in the September 2015 issue of Consumer Reports On Health.