Vaccine Basics

Why Are Vaccines Important?

Measles, mumps, and whooping cough may seem like quaint old illnesses confined to 19th century novels. But more and more teens are being exposed to them, especially in schools and on college campuses where large numbers of people are together in close quarters.

Diseases like measles, which were on their way out in the United States, are making a comeback as they are brought in from other countries by travelers. These diseases wouldn't spread as quickly — or be as serious — if people were immunized against them. But many teens aren't.

It's not your fault if you don't have all the immunizations (vaccinations) you need. Shots that doctors recommend today may not have been required when you were younger. So you may not have had them.

Some vaccines (like the HPV vaccine) are given as a series of shots, not just one single dose. Some people may have missed getting all the required shots. Not getting a full course of a vaccine leaves a person unprotected and still at risk for getting a disease. Other vaccinations require a booster shot every few years to ensure that the level of immunity remains high.

Why Do I Need Shots?

Missing a shot may not seem like a bad thing — nobody wakes up in the morning thinking they'd love to go out and get a jab in the arm. But there are good reasons to get shots:

One little "ouch" moment protects you from some major health problems. For example, older teens and adults who get diseases like mumps may be at risk for side effects of the illness, such as infertility (the inability to have children).

Vaccinations are about protecting you in the future, not just as a kid. Many of the diseases that we are vaccinated against when we're kids — like hepatitis B or tetanus — actually affect more adults than kids. Plus, anyone can get "kid diseases" like chickenpox, and they can be far more dangerous to teens and adults than they are to little kids.

Shots could even save your life. Hepatitis B attacks the liver and can eventually kill. The HPV vaccine can protect against several types of cancer. And scientists are constantly working on new vaccines against deadly diseases like HIV.

Which Vaccines Do I Need?

So which vaccines should you be getting? Doctors now recommend that teens are vaccinated against the following diseases:

• diphtheria, tetanus, and pertussis (called the Tdap vaccine)
• measles, mumps, rubella (the MMR vaccine)
• hepatitis A
• hepatitis B
• meningococcal disease (e.g., meningitis)
• human papillomavirus (HPV)
• varicella (chickenpox) if you have not had the disease
• polio
• flu (influenza)
• COVID-19

You can still get a shot if you've missed it. If you've missed some shots in a series of vaccines, you don't need to get the whole series again — you can simply pick up where you left off.

Some people may need more vaccines than the ones listed above. For example, people with diseases that affect their immune system (like diabetes, HIV infection, or cancer) should get a pneumococcal vaccine. People who live in areas where dengue is common need a dengue vaccine after they’ve had dengue fever. People who travel abroad may need to get special immunizations, depending on which country they'll be in. Since vaccines can take a while to start working, ask your doctor well in advance which immunizations you'll need. If you're pregnant, ask your doctor if there are any vaccines you should get.

How Do I Find Out If I've Had the Right Vaccinations?

Ask a parent to contact your pediatrician or family doctor so he or she can check your health records.

If you've already had a disease like chickenpox, you won't need the vaccine. And if it turns out you missed one or more of the required immunizations, you can still get them from your doctor — it's never too late. After getting a vaccination, it generally takes 10 days to 2 weeks for the body to build up immunity to a disease.

Once you have a certificate from your doctor that you've had all your shots, keep it filed away so you can find it easily later. If you plan to go to college, you will need to show proof that you've had a condition or been immunized. Some jobs also require proof of immunization — for example, if you are working or volunteering in a hospital.

Because some teens may have missed getting certain shots, this is one of those times when you need to take charge of your health: Bring up the subject of immunization when you see your doctor and ask if you've had all the recommended vaccinations (not easy, we know — but necessary!).

Are Vaccines Safe?

Like any medicine, vaccines may cause side effects, but receiving one is far safer than getting the disease it prevents. The most common reactions include soreness, redness, and swelling in the area of the shot or a low-grade fever. Usually acetaminophen or ibuprofen will take care of these side effects.

It's rare to have any kind of bad reaction to a vaccine. If you've had reactions to vaccines in the past, let your doctor know. Before getting a vaccine, discuss any concerns that you have about it with your doctor.

Who Should Not Be Vaccinated?

People who have a weakened immune system (from AIDS or certain cancers, for example) need to talk to their doctors before getting vaccinated. This is also true for those who receive treatments like chemotherapy or who take medication that can weaken the immune system. Girls who are pregnant can benefit from some immunizations (like the Tdap or flu shot) but should talk to a doctor or health clinic before getting vaccinated.

People with certain allergies may not be able to get some vaccines. For example, people who have severe allergies to gelatin or the antibiotic neomycin should be careful with the MMR and varicella vaccines. And if you're extremely allergic to baker's yeast, which is used to make bread, you should not get a hepatitis B vaccine. If you have allergies, talk to your doctor to see if any vaccine should be avoided.

Still Dreading That Shot?

We usually think of vaccines as shots, but not all vaccines are given that way. Some are given orally (by mouth) or in other forms like nasal sprays.

But it's impossible to escape the fact that some immunizations are just best given as shots. And it's completely normal to feel nervous about them. If you're one of the many people who dread shots, you can try a few techniques to make shots easier, like taking calming breaths and even coughing as the needle goes in.

The good news is that the shot itself only lasts for a second, but you'll be protected for a long, long time after that!