Questions & Answers

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When did diphtheria vaccine become available?
The first inactivated toxin, or toxoid, against diphtheria was developed around 1921, but it was not widely used until the 1930s. In the 1940s, diphtheria toxoid was combined with pertussis vaccine and tetanus toxoid to make the combination DTP vaccine.

In 1991, DTaP vaccine was licensed in the United States. The diphtheria component of this combination vaccine is the same as in the DTP vaccine; however, the pertussis component is a more purified "acellular" version, which produces fewer side effects.

In 2005, two new tetanus toxoid-diphtheria-acellular pertussis (Tdap) vaccines were licensed. These vaccines are the first pertussis-containing vaccines that can be given to persons older than 7 years.

Diphtheria is not available as a single vaccine.

What kind of vaccine is it?
The diphtheria vaccine is an inactivated toxin called a toxoid. It is made by growing the bacteria in a liquid medium and purifying and inactivating the toxin.

What's the difference between all the vaccines containing diphtheria toxoid?
Children younger than age seven years receive DTaP (diphtheria/tetanus/acellular pertussis). If they cannot receive the pertussis component of the combined vaccine, they can receive DT (diphtheria/tetanus). DTaP also can be given as part of two different combination vaccines; one includes DTaP, polio, and hepatitis B vaccines, and one contains DTaP and Hib vaccines.

Children seven and older and adults receive a different vaccine - either Td or Tdap.

How is this vaccine given?
The diphtheria vaccine is given as a shot in the muscle.

Who should get this vaccine?
Infants should receive DTaP vaccine (or DT if they cannot receive the pertussis component) as part of their routine immunization. Adults should be given a routine booster dose of Td every 10 years. Adults without documentation of ever receiving the basic series of tetanus and diphtheria toxoids should first receive a primary series of three doses, properly spaced. A single dose of Tdap is recommended for persons age 11 years and older in place of one of the Td doses, preferably the first one.

How many doses of DTaP vaccine are required?
The usual schedule for infants is a series of four doses given at two, four, six, and 15-18 months of age. A fifth shot, or booster dose, is recommended at 4-6 years of age, unless the fourth dose was given late (after the fourth birthday).

Because immunity to diphtheria wanes with time, individuals should receive a booster dose of Td (adult tetanus and diphtheria) every ten years. The new Tdap vaccine can be substituted for one booster dose of adult Td.

Should adults who weren't immunized as children receive this vaccine as adults?
Yes. Adults or children seven years and older without documentation of tetanus and diphtheria vaccination should receive a primary series of three doses of Tetanus-diphtheria toxoid (Td). The first two doses should be separated by 4-8 weeks, and the third dose given 6-12 months after the second dose. Tdap vaccine can be substituted for one of these three doses, preferably the first dose for persons 11 years and older.

Who recommends this vaccine?
The Centers for Disease Control and Prevention (CDC), the American Academy of Pediatrics (AAP), and the American Academy of Family Physicians (AAFP) all recommend this vaccine.

How safe is this vaccine?
Most people have no serious reactions from this combined vaccine. The most common reactions are local reactions at the injection site, such as soreness, redness, and swelling. Other possible reactions may include fussiness, mild fever, loss of appetite, tiredness, and vomiting. The use of the more purified DTaP instead of DTP has decreased even these mild reactions.

What side effects have been reported with this vaccine?
Moderate to serious reactions are uncommon with DTaP vaccine. Such reactions include crying for three hours or more (up to about one child out of 1,000) and high fever (about one child out of 16,000). More serious reactions such as seizure are even rarer.

For adults receiving Td vaccine, localized non-serious side effects are common (redness, soreness, etc.) but are generally self-limiting and require no treatment. Receiving more doses than recommended of any tetanus toxoid-containing vaccine can lead to increased local reactions, such as painful swelling of the arm, so it important for adults to keep an up-to-date record of all their vaccine doses.

The most frequently reported side effects following vaccination with Tdap were headache, generalized body aches, and tiredness.

How effective is this vaccine?
Approximately 95% of individuals have a protective level of antitoxin in their blood after a properly spaced primary series of vaccine (four doses of DTaP for young children, three of Td/Tdap for adults).

Who should NOT receive diphtheria vaccine?
People who have had a serious allergic reaction to one dose of DTaP, DT, Td, or Tdap vaccine should not receive another. Persons with a moderate or severe illness should postpone receiving the vaccine until their condition has improved.

Can the vaccine cause diphtheria?
No.

Questions and answers about diphtheria disease

Technically reviewed by the Centers for Disease Control and Prevention, February 2007