Vaccine programs for children have been extremely successful against many diseases, including measles, rubella, tetanus, diphtheria, and polio. In fact, fewer than 500 children die each year in the United States (US) from diseases that can be prevented with vaccines. However, adults also need vaccines, even healthy adults (Table 1). Each year in the US, there can be anywhere from 3,000 to 49,000 people who die from complications associated with the seasonal influenza (flu) virus. And more than 200,000 people are hospitalized each year for respiratory and heart illnesses also associated with seasonal flu infections.

When you are sick, your body creates antibodies to fight the infection. Later, if you are exposed to the same virus or bacteria, these antibodies will keep you from getting sick again. Vaccines help the body create antibodies without first getting sick. Even though you won't get the illness, the vaccine helps your body make antibodies to protect you from that illness.

Many adults remain unvaccinated because they:

  • Are unaware of the need for adult vaccines

  • Mistakenly believe they are fully protected by childhood vaccinations

  • Are misinformed about the diseases vaccines prevent

  • Feel they don't need vaccinations because they are healthy and rarely get sick

  • Are worried about getting the disease from the vaccination

  • Are worried about the safety of the vaccine itself.

What vaccines do I need?

There are currently 11 vaccines recommended for adults (Table 1) on the basis of age, prior vaccinations, health conditions, lifestyle, occupation, and travel. Some are recommended for all adults within a specific age bracket who were not previously vaccinated or infected with the bacteria or virus. Others are recommended only if some other risk factor is present, such as travel or kidney disease. The Centers for Disease Control and Prevention (CDC) offers a quiz that people 11 years and older can take to learn exactly which vaccines they may need. The quiz can be found on the Internet at: It takes just a few minutes to answer the questions. Upon completing the quiz, you will be able to view and print a form that lists the vaccines you may need and why they are recommended. Just take the list to your doctor. Be sure to tell your doctor if you have already had any of these vaccines or diseases. Also tell your doctor about any food or drug allergies you have.

Why aren't childhood vaccines enough?

The protection provided by some childhood vaccines decreases as you grow older. Thus, many of the vaccinations we had as children need to be given again when we are adults to keep us protected. For example, recent outbreaks of whooping cough (pertussis) have been reported in adults who had been vaccinated against the disease as a child. Getting vaccinated against pertussis as an adult can boost your immunity and help prevent the disease during adulthood. In addition, certain vaccines may not have been available when some adults were children, or the recommendations for when and how often the vaccinations are needed may have changed. So, older adults born at a time when children were not vaccinated as comprehensively may need to be vaccinated as an adult. The body's defense against illness—called the immune system—also weakens as you grow older and can increase your risk of developing certain illnesses caused by common infections like the flu and pneumonia. Finally, some vaccines are just for adults. The zoster vaccine to protect against shingles is an example—this vaccine is recommended only for adults 60 years and older. So, even if you received all your childhood vaccinations, you will still need to be vaccinated as an adult.

Why can't I skip adult vaccines if I am otherwise healthy?

Many people skip vaccinations because they believe it will just be a minor inconvenience if they develop the diseases that vaccines prevent. However, some vaccine-preventable diseases can be serious or even fatal. In addition, getting vaccinated is the best way to both prevent these illnesses in you and prevent you from spreading them to others. Even if you rarely get sick, you can still become infected with the influenza virus (that causes the flu) or pneumococcus (one of the causes of pneumonia) but have mild or no symptoms. However, you are still contagious and can pass the illness on to others around you. So, getting vaccinated helps protect others around you as well as yourself.

This type of disease protection is called herd immunity ( because the idea is you can live safely within the herd if enough of the herd is vaccinated. As the number of vaccinated people grows, the spread of disease from one person to another is limited. Thus, vaccinated individuals can help protect the half million people nationwide who cannot be vaccinated due to allergies or other medical reasons.

Can I get the disease from the vaccine?

Vaccines are specifically designed to produce immunity without causing illness. There are 4 types of vaccines:

  • Inactivated or killed vaccines are made from viruses or bacteria that have been killed by chemicals or heat. You can't develop an illness because the virus or bacteria cannot reproduce. Theses vaccines tend to have fewer side effects; the tradeoff is a weaker immune response than vaccines that use weakened live viruses and bacteria. Thus, vaccine boosters are often required

  • Live or live attenuated vaccines are designed to produce an immune response similar to a natural infection. The virus or bacteria is weakened to produce an infection without causing illness and without the ability to spread the infection to others. These vaccines are more likely to cause mild side effects and cannot be given to people with weak immune systems. Only vaccines made from live viruses carry even the smallest risk of developing the actual illness—which is an extremely rare event.

  • Subunit/conjugate vaccines are made from a specific part of the virus or bacteria or a specific protein or carbohydrate that produces a protective response in the body. These parts of the virus or bacteria may be linked—or conjugated—to another common protein to increase the immune response. These vaccines are unable to reproduce and cause illness.

  • Toxoid vaccines contain a toxin or other chemical made by the virus or bacteria that help protect against the harmful effects of an infection rather than the actual infection. These vaccines do not contain the virus or bacteria and cannot cause disease.

In general, vaccines take approximately 2 weeks to work. So protection from a vaccine will not occur immediately after vaccination. For example, it may take several weeks to develop immunity from the flu vaccine. If you are exposed to people with the flu before you have full immunity, you could get the disease but it may be milder than if you didn't get the vaccine. It is important to remember that vaccines are many times safer than the diseases they prevent.

What side effects can I expect?

Adult vaccine side effects are typically mild and may include a mild fever, redness and tenderness at the site of injection, and a mild skin rash. Severe side effects are rare but may include seizures or a severe allergic reaction. A particular vaccine may not be recommended for people with serious allergic reactions to eggs or egg protein, neomycin or streptomycin, gelatin, or a specific vaccine.

Vaccines are widely considered one of the greatest public health achievements. However, current vaccination levels in adults are low. We encourage all adults to take the quiz mentioned above to learn which vaccines are recommended for you, and to take the list to your healthcare provider. Your healthcare provider is the best source of information for questions about vaccines. Getting vaccinated is a lifelong job, not just a childhood rite of passage.

Source: Vaccinate Adults (

*Table does not include intervals between doses and other important information. Also, other vaccines or vaccine schedules may be recommended for adults based on medical and other indications.

Judy L. Smetzer is the Vice President of ISMP.

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