The Diphtheria/Tetanus/Pertussis Vaccine

What It Is and What It Protects Against

There are four vaccines to protect against diphtheria, tetanus, and pertussis:

• DTaP: given to children under age 7
• DT: given to children under age 7
• Tdap: given to older children and adults
• Td: given to older children and adults

*What the letters mean:  DTaP, Tdap, and Td are all similar vaccinations given for the same diseases at various times in a person’s life. Depending on age, certain amounts of each of the vaccine’s components are administered. The lettering system and upper/lower cases denote the component of the vaccination and the amount that’s included within. As the CDC explains, “Upper-case letters in these abbreviations denote full-strength doses of diphtheria (D) and tetanus (T) toxoids and pertussis (P) vaccine. Lower-case “d” and “p” denote reduced doses of diphtheria and pertussis used in the adolescent/adult-formulations. The “a” in DTaP and Tdap stands for “acellular,” meaning that the pertussis component contains only a small part of the pertussis organism.”

General Use 

• DTaP: DTaP protects against three diseases: diphtheria, tetanus (lockjaw), and pertussis (whooping cough). The CDC recommends that children receive five doses of this vaccine, administered at specific ages, beginning at 2 months old. The second dose should follow at 4 months; the third dose at 6 months; the fourth dose between ages 15 to 18 months; and the fifth and final dose between 4 to 6 years old. DTaP is not licensed for older children, adolescents, or adults.
• T: This is a booster shot which is recommended every 10 years. The Td vaccine protects against tetanus and diphtheria, but not pertussis.
• Tdap: Unlike the Td vaccine, the Tdap protects against all three diseases. For protection as you age, adolescents (between age 11 to 18) and adults (between 19 to 64 years old) can receive one dose of Tdap. This vaccine may also be given to children between ages 7 to 10 who are not completely immunized against pertussis.  This vaccine is also recommended for adults because there is an increasing incidence of pertussis in infants who have yet to be fully immunized but have been exposed to adults whose immunity is waning.

Who Should Not Get It

According to the CDC, the introduction of vaccines has led to the decrease of tetanus cases by more than 96 percent and diphtheria by more than 99 percent. Routine vaccines are recommended for children, adolescents, and adults; however there are certain people who should not get the diphtheria, tetanus, and pertussis vaccines, including:

• people who had severe allergic reaction to past doses of DTP, DTaP, DT, or Td
• people who had severe allergic reaction to any component of a vaccine
• people who had a coma or seizures within 7 days after receiving the DTP or DTaP vaccines
• anyone who is moderately to severely ill is advised to wait until a full recovery before getting vaccinated 

In addition to the above list, there are additional factors that may affect a person’s risk for receiving the Tdap vaccine. Other concerns to discuss with your doctor before getting the Tdap include:

• having epilepsy
• experiencing severe swelling from past doses of DTP, DTaP, DT, Td, or Tdap
• having Guillain Barré Syndrome (GBS)

Potential Side Effects

Though the risk of serious harm from these vaccines is small compared with the risk of getting the diseases, the vaccines do hold some risk, from mild to severe side effects.

Mild side effects include:

• soreness or swelling where the shot was given
• fever
• fussiness
• fatigue
• vomiting

Moderate to severe side effects include:

• seizure (jerking or staring)
• continuous crying
• high fever
• permanent brain damage