According to experts, the answer is clear: vaccinations.
"Immunizations are the greatest medical advance of the last 100 years," says Richard L. Wasserman, MD, PhD, clinical professor in the department of pediatrics at the University of Texas Southwestern Medical School in Dallas.
"There's no question that immunizations have done more good for more people than any other medical intervention," agrees Ricardo U. Sorenson, MD, chair of the department of pediatrics, Louisiana State University Health Sciences Center in New Orleans.
Vaccinations have essentially wiped out diseases that once infected hundreds of thousands of people every year and killed tens of thousands. Yet many of us take immunizations for granted and may assume that, once we're adults, we don't need them anymore.
We do. While we may outgrow our need for booster chairs, we never outgrow our need for booster shots. So if you suspect you're not up-to-date with your vaccinations, it's time for a checkup.
Why Get Immunized?
Vaccines don't get the credit they deserve - a testament to their success. Vaccines have so effectively wiped out many diseases that these illnesses seem as extinct as dinosaurs.
"How many people do you know who have had diphtheria or tetanus?" asks Wasserman. "Probably none. That's how well vaccines work."
Sorenson agrees that, nowadays, we have a casual attitude toward the diseases that terrified our grandparents. "People tend to forget how serious diseases like measles, mumps, rubella and whooping cough were because they haven't experienced them," he tells WebMD.
But what's risky about our casual attitude is that these diseases are not extinct. In some parts of the world, they're common. If people stopped getting vaccinated in the United Sates, they would become common here.
"I've seen the results of not getting vaccinated," says Wasserman. "I've seen children sick with vaccine-preventable diseases, like whooping cough and polio. It's tragic."
Why Do Adults Need Vaccinations?
Many vaccines work by introducing a dead or weakened version of a germ into your body, allowing your body to become familiar with it. Your immune system then reacts by creating antibody proteins custom-designed to fight that particular microbe. Then, if you ever come into contact with the real germ, the antibodies attack it. This is how vaccines grant you immunity.
However, that immunity doesn't necessarily last forever. Those antibodies may fade away with time.
"After age 30 or so, the potency of immunity wanes," Wasserman says. "In the same way that your muscle strength fades after middle age, the vaccine immunity that protected you when you were young loses its strength when you're in your 40s, and 50s, and 60s."
Happily, the solution is simple: get a booster shot. This is a way of reminding your immune system how to fight the microbe.
In addition to boosters, you need other vaccines as you get older and your risk of getting certain diseases increases.
Vaccinations Benefit Others
Obviously, getting a vaccination protects you from getting sick, but vaccines have a greater benefit: they protect the people around you from getting sick.
It's a phenomenon called "herd immunity." If most people in a group are vaccinated against a disease, even the people who aren't vaccinated are much less likely to get it.
This reason for vaccination is important, because vaccines can be dangerous for some people. For instance, some are too sick to handle a vaccine or are allergic to it, but if the people around them are vaccinated, they are more likely to be safe. "It's an indirect way of protecting them," says Wasserman.
There's also a flip side. If you live with someone with a compromised immune system from a disease or its treatment - like chemotherapy - tell your doctor before you get vaccinated. The weakened version of a virus in a vaccine could spread from the vaccinated person to the ill family member. Sometimes, even the weakened virus is dangerous for a person with a compromised immune system.
Which Immunizations Do Adults Need?
The vaccinations you need depend on your age, health and vaccination history. But here's a rundown of some of the common vaccines adults should get.
The CDC recommends that all adults have a diphtheria/tetanus booster shot every 10 years. "Diphtheria is still a rare disease these days, but it's most common in people over 65," says Wasserman. "Continued vaccinations are important."