How Do Vaccines Work? Here's What You Should Know : Life Kit Just because you (or your kids) are home all day doesn't mean you can skip your vaccines, including a flu shot. Here's how vaccines work and why they're important this year.

Vaccines 101: How They Work And Why You Need Them

Vaccines 101: How They Work And Why You Need Them

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Samya Arif for NPR
Samya Arif for NPR

Updated March 01, 2021

Vaccines are on a lot of people's minds these days.

And while the COVID-19 vaccine may or may not be available to you right now, staying on top of your regular vaccines can keep you healthy — and maybe even save your life.

Staying on top of all those vaccines can be confusing. To help answer some of your most common questions, we talked to Dr. Melissa Martinez, a family physician and professor at the University of New Mexico.

"Vaccines are a gift not only to us, but to future generations," she says.

Martinez loves vaccines. But when she was a new mom, she admits she was skeptical about the side effects of giving her kids all of those shots.

"I looked at the evidence, I looked at the science behind vaccines, and I realized that by getting my children vaccinated, I was protecting them," she says. "I was also protecting all the other children in their community."

These days, Martinez helps spread the word about vaccines as a member of the National Vaccine Advisory Committee, where she helps direct their work on equitable access to immunizations. Here, Martinez shares her tips about staying up to date.

Think of her advice as "Vaccines 101."

Vaccines prepare your immune system to fight off infections

Vaccines are hardly a new invention. Martinez says there's evidence that people in 16th century China understood that people who were exposed to a disease already were less likely to get infected again.

Modern vaccines work by exposing the body to a tiny, harmless part of a virus or bacteria. It stimulates the body's immune response, meaning your body generates antibodies and other types of cells to help fight off a future infection.

"The next time you're exposed to the real virus, you don't get sick," Martinez says.

Side effects can happen, but they're usually mild

When the vaccine stimulates your body's immune response, it gears up to create an army of immune cells that are primed to fight off viruses and bacteria.

Creating that army is hard work! That's why you might experience an achy arm at the site where you were vaccinated, or a low grade fever. Those side effects mean the vaccine is working, and they usually go away with over-the-counter painkillers.

"Their body is responding, their immune system is acting up," she says.

Life-threatening side effects are incredibly rare, Martinez adds. Vaccines do not cause autism or brain damage.

In fact, she adds, vaccines are one of the safest treatments we have in medicine.

If your kids are in virtual school, don't skip out on back-to-school vaccines

With so many kids in virtual school this fall, families might be tempted to delay their children's well-child appointments with the doctor.

"Nobody wants to go to a doctor and be in a crowded waiting room during this time," Martinez says.

But don't let your kid's vaccines fall through the cracks! Martinez recommends calling your child's doctor and asking about socially distant options for your family's vaccines.

In Martinez's practice, for example, they're offering drive-through shots where a clinician comes out to your car to give you your vaccines. You can also try your pharmacy or local public health department as an alternative to the doctor's office.

Martinez also suggests keeping a record of your family's vaccines, so that if you do go to a pharmacy, you can keep your doctor updated. The same advice applies if you move or change doctors. If you want to see what vaccines you might need, you can check the Centers for Disease Control's recommendations for children and adults.

Flu shots are extra important this year

Getting your yearly influenza shot is extra important this year.

"A lot of people every year die from the flu. So we already have a great deal of deaths occurring with COVID and we don't need flu deaths," Martinez says. "We need to keep people well and out of hospitals."

The flu is not the common cold. It's much deadlier, and the influenza virus is constantly adapting to outsmart our treatments and vaccines. That's why getting the flu vaccine every single year is so important: the vaccine is designed to help your body fight off the strain that is developing this year.

Many people think the flu shot makes them sick. Like other vaccines, it can make you feel achy and sore, but Martinez says that usually goes away with ibuprofen. It's a small price to pay for protecting yourself — and your loved ones — from a dangerous virus.

"The flu shot can make some people feel really, really cruddy," Martinez says. "But getting the flu would make people feel so much worse."

She suggests getting your shot before the end of October to make sure you're protected through the peak of flu season, which is usually at its worst from December through February.

Pregnant people and older people have weaker immune systems, so they should be extra vigilant about staying updated

Pregnant people should get an annual flu shot, since they can be particularly susceptible to influenza.

"Every pregnant woman should get a flu shot because if a pregnant woman gets the flu, she's a lot more likely to get severely ill," Martinez says.

All pregnant people should also get a Tdap shot during prenatal care, which protects against tetanus, diphtheria, and pertussis. Protection from pertussis — sometimes known as whooping cough — is particularly important for new parents, since it can be dangerous for newborns.

During pregnancy, people should avoid live vaccines, which are made with a weakened form of a real virus. This includes the measles, mumps, and rubella vaccine.

Older adults should also make sure they get their yearly flu shot. They should also get vaccinated against shingles and get the pneumococcal vaccine, which protects against life-threatening bacterial infections.

Your immunity can wane over time, so ask your doctor if you need a booster

Vaccines help your body generate immune cells to fight off infection, but those immune cells can lose their strength over time. That's where booster shots come in: they jumpstart your body's defenses.

Doctors recommend certain booster shots to everyone: most people should get Tdap every ten years.

But not everyone needs to get checked for immunity, unless you've been exposed to an infection or there's an outbreak of a particular disease in your community.

People who work in health care are often required by their employers to get blood tests that show they have immunity, and if their antibody levels are low, they'll need to get revaccinated.

If you have specific questions about vaccines, you can always ask your doctor. What she recommends will depend on your medical history and your risk factors, so don't be afraid to speak up at your next appointment. You can use this CDC quiz to see what might be right for you.

"Vaccines are one of the great achievements of mankind," Martinez says. "If we can protect against those diseases, let's do it.

The podcast portion of this episode was produced by Andee Tagle.

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