Essential Facts About the Tdap Vaccine

3-in-1 vaccine recommended for adolescents and some adults

Most of us have been vaccinated with the tetanus diphtheria (Td) vaccine, given to protect us from those two potentially serious diseases. There is another vaccine recommended for adolescents and adults that can protect against more than just tetanus and diphtheria.

Known as the Tdap vaccine, the shot also protects against a disease called pertussis (whooping cough), as well as the two aforementioned diseases.

A nurse putting a bandaid on child's arm

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Tetanus is caused by a bacteria that enters the body through breaks in the skin and open wounds. Commonly known as lockjaw, tetanus causes a painful tightening of the muscles, including the mouth and jaw. If left untreated, tetanus can be fatal in up to 20% of cases.

While it is relatively rare in the United States, certain populations are at potentially greater risk of infection. 

Symptoms include spasms of the jaw muscles that progress to neck stiffness, difficulty swallowing, and the tightening of the abdominal muscles. Fever, sweating, high blood pressure, and increased heart rate are also typical.


Also caused by a bacteria, diphtheria causes a thick covering to form in the back of the throat. Left untreated, diphtheria can lead to breathing difficulty, swallowing problems, and heart failure. In extreme cases, paralysis and even death can result.

Diphtheria is usually spread by person-to-person contact or through the air. In some cases, it can also be spread by contaminated objects. Infected individuals can carry the bacteria without having any symptoms, but can still spread the disease to others.

While the disease is considered rare in the U.S. and in the developed world—with around 5,000 new cases every year—it was only in the 1970s that yearly cases dipped below 200 in the U.S. Although only five cases have been reported since 2000, there is concern that older adults with waning antitoxin antibodies may be at risk.


Pertussis (whooping cough), a bacterial infection, causes a very distinctive cough that sounds quite literally like a whoop. The severe coughing spells that result can cause vomiting and sleep disturbances. Untreated, pertussis can lead to weight loss, rib fractures, pneumonia, and even hospitalization.

While in the 1980s and 1990s there were fewer than 3,000 pertussis cases per year, the disease has since surged, and there are now upwards of 20,000 cases of pertussis each year. It is particularly dangerous—even deadly—for infants.

It is an airborne disease that can be transmitted by sneezing and coughing. People are infectious from the very start of symptoms until about two weeks into the coughing fits. The time between infection and the onset of symptoms is usually between seven and ten days.

Who Should or Shouldn't Get Vaccinated

It is currently recommended that adolescents be given the Tdap vaccine, preferably at 11 to 12 years of age. If they do not, then they should get it as a catch-up vaccination between ages 13 and 18. There is no longer a 2- to 5-year gap recommended if the adolescent received a tetanus vaccination.

The CDC advises pregnant women to receive the Tdap shot between 27 and 36 weeks of each pregnancy. Because babies can't receive the childhood version of the shot—called DTaP—until 2 months old, there's a window of time when they're not protected from pertussis. By getting vaccinated during the third trimester, a mother can pass those protective antibodies to her child.

Adults who have not previously received Tdap at or after age 11 years should get 1 dose of Tdap, then Td or Tdap every 10 years. The indication for Tdap in HIV-positive people is the same as in HIV-negative people.

Administration of the Tdap vaccine is contraindicated in anyone who has had a severe allergy of any of the components of the tetanus, diphtheria, or pertussis vaccines.

Additionally, persons who have a known latex allergy should talk with their doctor before receiving the shot. They may be able to provide the vaccination from a latex-free vial or syringe. Anyone with a history of seizures, epilepsy, or Guillain Barré syndrome should also notify their doctor before receiving the vaccine.

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Side Effects

Side effects of Tdap vaccination are typically classified as low grade, resolving on their own within a day or two on average. They include:

  • Pain, redness, or swelling at the injection site
  • Fever
  • Headache
  • Fatigue
  • Nausea, vomiting, or diarrhea
  • Rarely, body aches, chills, joint pain, or swollen lymph glands

If these symptoms are either severe or persist, contact your doctor or clinic immediately.

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Article Sources
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  1. Centers for Disease Control and Prevention. Tetanus: symptoms and complications. Updated February 28, 2019.

  2. Centers for Disease Control and Prevention. Diphtheria. Updated April 15, 2019.

  3. Centers for Disease Control and Prevention. Pertussis. Updated April 15, 2019.

  4. Liang JL, Tiwari T, Moro P, et al. Prevention of pertussis, tetanus, and diphtheria with vaccines in the United States: Recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep 2018;67(No. RR-2):1–44. DOI:doi:10.15585/mmwr.rr6702a1

  5. Centers for Disease Control and Prevention. Epidemiology and prevention of vaccine-preventable diseases, 13th Edition. Updated May 2019.

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