What Is the Tdap Vaccine?

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The Tdap vaccine protects against a disease called pertussis (whooping cough), as well as tetanus and diphtheria. This life-saving vaccine is recommended for adolescents and adults, beginning at age 11 or 12. Boosters every 10 years are given throughout adulthood. The vaccine is especially important during pregnancy as it protects the new baby. Children ages 7 to 10 may also be given the vaccine if they did not get the recommended doses of the DTap vaccine in childhood.

Diseases Tdap Prevents

Tetanus, diphtheria, and pertussis are all caused by bacterium which, if left untreated, can cause serious illness and death. These are preventable diseases, which have been made much less common due to the use of vaccines.


Tetanus, which is also commonly referred to as "lockjaw," causes painful muscle tightening, especially of the head and neck. This muscle tightening makes it difficult to open the mouth, swallow, and breathe. Tetanus enters the body through cuts or wounds.

Tetanus is not common in the United States due to the widespread use of the vaccine. There are now just an average of about 30 reported cases each year. However, of those that contract tetanus, one in 10 die from the illness. According to the Centers for Disease Control (CDC), among those who do contract tetanus, most either never got a tetanus vaccine or did not complete the schedule of shots.


Diphtheria is a type of bacteria that causes an infection in the mouth, nose, and throat. The communicable disease potentially can affect breathing, heart failure, paralysis, and/or cause harm to other organs from bacteria-produced toxins.

Symptoms of diphtheria appear two to five days after exposure and may include damage to the heart, kidneys, and nerves (if the bacteria enter the bloodstream), fever, swollen lymph nodes, weakness, and a thick, gray coating in the nose, mouth, or throat.


Pertussis is a highly contagious respiratory disease spread by coughing, sneezing, or simply being in the same airspace as an infected person for an extended time. In the last 20 years, rates of pertussis have been rising in very young infants who don't yet have their immunizations and in unvaccinated adolescents and adults. Pertussis is especially serious for infants under age 1, and can even be fatal.

Symptoms of pertussis appear within five to 10 days of exposure and may include apnea (gaps in breathing), fatigue, a high-pitched "whooping" cough that lasts two weeks or more, low-grade fever, pneumonia, vomiting, and spells of coughing and choking that make breathing difficult.

Types of Tdap Vaccines

There are two Tdap vaccines approved by the Federal Drug Administration (FDA): Adacel and Boostrix, both of which include the tetanus toxoid (T), reduced diphtheria toxoid (d), and acellular pertussis (ap) vaccine in a single shot.

According to the CDC, upper-case letters (”T” in Tdap) mean the vaccine has full-strength doses of that part of the vaccine, while the lower-case letters (“d” and “p” in Tdap) mean the vaccine contain smaller doses of medicine to combat those illnesses. The vaccine is made with reduced quantities of the same antigens that are in the Infanrix DTaP vaccine that many kids already get.

Like most newer vaccines, Tdap vaccines are preservative-free. This means they do not contain thimerosal, a mercury-based additive sometimes added to vaccines to prevent germ growth. There is no reputable evidence of a link between thimerosal and autism, but misinformation and worry prompted scientists to remove the preservative from many vaccines.

Who Needs a Tdap Vaccine?

According to the CDC, the Tdap vaccine is currently recommended for a variety of groups. These include kids between ages 7 and 10 years who were not fully vaccinated with other whooping cough vaccines, like DTaP, and kids between ages 11 to 18, with preferred administration at ages 11 through 12 years.

Additionally, adults ages 19 and older are recommended to get the vaccine as a one-time dose, followed by a Td or Tdap booster every 10 years. Pregnant individuals between 27 and 36 weeks of each pregnancy should also get Tdap. Getting the vaccine during the third trimester provides antibodies to protect the baby until they can receive the childhood version of the shot—called DTaP—at 2 months old.

Tdap vaccination is especially crucial during pregnancy as research shows that 43% of infants 6 months and younger who contract pertussis end up in the hospital. Moreover, children under age 1 make up 70% of the deaths from this illness.

Seniors over the age of 65 should also get the vaccine if they are going to have close contact with a newborn or infant less than 12 months of age. Likewise, healthcare professionals who have not previously received Tdap and who have direct patient contact are also advised to get the shot.

You should notify your doctor and possibly avoid the Tdap vaccine if you've had a past allergic reaction to any of the vaccine ingredients, especially those in the tetanus vaccine.

Additionally, the vaccine may be contraindicated if you experienced a coma or seizures within a week after receiving DTaP, the childhood vaccine for pertussis, you have a latex allergy (although you may be able to receive the shot via a latex-free vial or syringe). You also may need to avoid the shot if have a history of seizures, epilepsy, or Guillain-Barré syndrome.

How Effective Are Tdap Vaccines?

Overall, the Tdap vaccine is effective and strongly recommended. However, the pertussis portion of the Tdap vaccine doesn't work as well as experts would like. Unfortunately, the immune protection seems to wane fairly quickly.

According to the CDC, the vaccine protects 95 in 100 people from diphtheria for approximately 10 years. It also protects almost everyone from tetanus for roughly 10 years. Additionally, roughly 7 out of 10 people won't get whooping cough in the first year after getting Tdap, and three or four in 10 people four years after getting the shot.

Preventing Pertussis

In addition to getting your Tdap vaccine, the CDC advocates practicing good hygiene to prevent pertussis. These recommendations include covering your mouth and nose with a tissue when you cough or sneeze, or coughing into your upper sleeve or elbow if you don't have a tissue. It's also important to wash your hands often, for at least 20 seconds, with soap and water. Use an alcohol-based hand sanitizer if you don't have access to soap and water.

Side Effects

Tdap vaccine side effects are typically mild and resolve on their own within a few days. The vaccine's side effects may include body aches, chills, diarrhea, nausea, vomiting, fatigue, fever, headache, loss of appetite, joint pain, rash, swollen glands, and pain, redness, or swelling at the injection site.

If side effects from getting Tdap become severe or persistent, contact your healthcare provider immediately.

History of Tdap Vaccine

Vaccines that provide protection against tetanus, diphtheria, and pertussis aren't new. The original DTP vaccine has been around since 1948, and DTaP since 1997. Before those combination vaccines, we had individual vaccines against each of these vaccine-preventable diseases. The Tdap vaccine first became available in 2005. It was the first vaccine to include pertussis protection for older kids and adults.

A Word From Verywell

The Tdap vaccine can be one of the best preventive measures a parent can take to protect themselves and their child against whooping cough, tetanus, and diphtheria. Talk to a healthcare provider today to make sure you and your family are up to date on this lifesaving medicine.

11 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Centers for Disease Control and Prevention. Tetanus.

  3. Centers for Disease Control and Prevention. Pertussis: summary of vaccine recommendations.

  4. Centers for Disease Control and Prevention. Diphtheria.

  5. Centers for Disease Control and Prevention. Pertussis (whooping cough).

  6. Food and Drug Administration. Tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine, absorbed.

  7. Federal Drug Administration. Thimerosal and vaccines.

  8. Wales DP, Khan S, Suresh D, Ata A, Morris B. Factors associated with Tdap vaccination receipt during pregnancy: a cross-sectional study. Public Health. 2020;179:38-44. doi:10.1016/j.puhe.2019.10.001

  9. Centers for Disease Control and Prevention. Epidemiology and prevention of vaccine-preventable diseases, 13th Edition.

  10. Centers for Disease Control and Prevention. Pertussis frequently asked questions.

  11. American Academy of Pediatrics. Tdap vaccine: what you need to know.

By Vincent Iannelli, MD
Vincent Iannelli, MD, is a board-certified pediatrician and fellow of the American Academy of Pediatrics. Dr. Iannelli has cared for children for more than 20 years.