If you’re guilty of skipping certain vaccines, you have plenty of company. Research shows that many older adults aren’t getting the protection they need. About 30 percent of people 65 and older skipped their flu shot last year, about two-thirds didn’t receive the recommended shingles vaccine, and 43 percent aren’t up to date on tetanus shots, according to a 2017 report from the Centers for Disease Control and Prevention.

But these vaccines are important for this age group. “As we get older, our immune system becomes much less ­robust, which means we’re not just more at risk for getting diseases like the flu and shingles but of developing life-threatening consequences from them,” says William Schaffner, M.D., an infectious-­disease specialist at Vanderbilt University in Nashville.

How Effective Are Vaccines?

The weakening immune system that age brings could also make vaccines somewhat less effective. “Your body doesn’t respond with quite as many antibodies as it would if you were younger,” Schaffner explains.

No matter what your age, keep in mind that vaccines don’t necessarily provide complete protection. Some, such as the tetanus shot, are reported to be 100 percent effective. But the flu shot generally cuts your risk of getting influenza only by about half. The effectiveness of certain vaccines also wanes over time, which is why boosters are recommended for certain diseases.

Still, “half a loaf of bread is better than none,” Schaffner points out. “If you get vaccinated and still get the flu—or other illnesses, like shingles—your illness is probably going to be much milder than it might have been. You’re much less likely to develop a life-threatening complication, much less likely to be admitted to the hospital, and much less likely to die.”

Here, the four shots that all older adults should be up to date on (your doctor might recommend others based on your health and preferences) and smart strategies to help you maximize vaccine effectiveness:

4 Key Vaccines

1. Flu vaccine. The once-a-year flu vaccine is a must for older adults. Up to 85 percent of seasonal flu-related deaths and 70 percent of seasonal flu-related hospitalizations are for people 65 and older, accord­ing to the CDC. The vaccine typically cuts risk by 40 to 60 percent. But rates can vary year to year depending on how well ­experts predict which strains will circulate in a given flu season. For the 2016 to 2017 flu season, the shot was only about 42 percent effective.

More on Vaccines

To improve your chances of escaping the flu, consider a vaccine designed for people 65 and older. According to the CDC, the Fluzone High-Dose vaccine contains four times the amount of antigen in regular flu shots. A 2014 study in the New England Journal of Medicine found that older adults who had this shot were 24 percent less likely to catch the flu than those who received a standard shot.

The second such vaccine, Fluad—designed to elicit a stronger immune system response than the traditional flu shot—has also been shown to offer more protection to seniors.

Flublok Quadrivalent, approved last year, appears to be more effective in older adults than the regular flu vaccine as well. Research published in The New England Journal of Medicine last June found that people 50 and older who ­received Flublok were 30 percent less likely to get the flu than those who received the standard vaccine.

Early fall is the ideal time to be vaccinated because flu season usually starts in late October and it takes about two weeks to fully build up immunity. But it’s never too late. “The flu usually peaks in February and then can circulate until April,” Schaffner says. If possible, get the vaccine in the morning. A study published last year in the journal Vaccine found that vaccines given between 9 a.m. and 11 a.m. led to higher levels of protective antibodies than those given between 3 p.m. and 5 p.m.

2. Pneumococcal vaccine. Older adults are more likely to develop complications such as pneumonia, blood infections, and meningitis from pneumococcal bacteria, says Kenneth Schmader, M.D., chief of the division of geriatrics at the Duke University School of Medicine. Pneumococcal disease kills about 18,000 adults 65 and older each year.

Two vaccines protect against pneumococcal disease—PCV13 (Prevnar 13) and PPSV23­ (Pneumovax 23). The CDC recommends that all adults 65 and older have both shots, a year apart, with the PCV13 first. It protects about 75 percent of older adults and PPSV23 shields up to 85 percent of healthy adults from invasive pneumococcal disease. But only about 18 percent of older adults get both vaccines, according to a study published in July in the CDC’s Morbidity and Mortality Weekly Report.

If you have diabetes; asthma; chronic lung, heart, kidney, or liver disease; or wear cochlear implants, talk to your doctor about earlier vaccination.

3. The shingles vaccine. Shingles, or herpes zoster, occurs when the chickenpox virus—dormant in almost all adults who had chickenpox in childhood—reactivates in later life. The condition often brings a blistering, painful rash. The blisters usually scab over in seven to 10 days and clear up in two to four weeks. But about 20 to 25 percent of people continue to experience mild to severe nerve pain (postherpetic neuralgia, or PHN) that can linger for months or even years. “That’s the most debilitating part of the disease,” Schaffner explains.

Zostavax, the vaccine currently on the market and recommended for adults age 60 and over, cuts the chance of shingles by 51 percent for five years and the likelihood of PHN by 67 percent. Its effectiveness seems to subside over time, and the likelihood of shingles rises as we age. So the vaccine might not be as robust as we need it to be when the risk of shingles is highest.

Last week the the Food and Drug Administration approved Shingrix, a new shingles vaccine, which was found in clinical trials to be about 90 percent effec­tive up to four years after injection. Manufacturer representatives say Shingrix should become available starting in late November.

4. Tdap vaccine. If you didn’t have the Tdap (tetanus, diphtheria, and pertussis) shot—the booster for the childhood DTaP vaccine—as a teen or an adult, get one now.

Making sure you’ve had the Tdap booster is especially important if you’ll be spending time around an infant. Pertussis, or whooping cough, is a highly contagious bacterial respiratory-tract infection that can be life-threatening for children younger than 12 months. And though it can cause significant symptoms in adults, some might have the illness without knowing it. Note that it takes about two weeks for the whooping cough part of the vaccine to become fully effective.

“Even if you were vaccinated against pertussis as a child, protection wanes over time,” Schmader explains. In fact, though the Tdap vaccine appears to safeguard most people from tetanus and diphtheria, and about 80 percent from pertussis, a 2016 Canadian study found that pertussis protection fell to 41 percent ­after eight years.

If you had the Tdap 10 or more years ago, get a booster against tetanus and diphtheria, called Td. You can get the Tdap only once, unless you’re pregnant.

Editor's Note: This article also appeared in the December 2017 issue of Consumer Reports on Health.