Questions & Answers

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When did pertussis vaccine become available?
The first whole-cell pertussis vaccine was developed in the 1930s and was in widespread use by the mid-1940s, when pertussis vaccine was combined with diphtheria toxoid and tetanus toxoid to make the combination DTP vaccine.

In 1991, DTaP vaccine was licensed in the United States. The pertussis component of this vaccine 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 acellular pertussis-containing vaccines that make it possible to vaccinate adolescents and adults against pertussis.

Pertussis is not available as a single vaccine.

What kind of vaccine is it?
DTaP and Tdap vaccines are "inactivated" vaccines. Inactivated vaccines do not contain live bacteria or virus and cannot reproduce, which is why multiple doses are needed to produce immunity.

For the pertussis component of DTaP and Tdap vaccines, purified components of the bacterium are grown and then inactivated. DTaP is for children younger than 7 years and has a higher concentration of pertussis than Tdap, which is intended for persons 10 years and older.

How is this vaccine given?
The DTaP and Tdap vaccines are given as a shot in the muscle.

Is there more than one brand of pertussis vaccine?
At the present time, there are three different brands of DTaP (pediatric) vaccines available in the U.S. All three vaccines are equally effective and safe, and are given on the same schedule (two, four, six, 15-18 months, 4-6 years). DTaP is also part of two combination vaccines. Two companies produce the Tdap vaccines. The vaccines are approved for use in different age groups (10-18 years and 11-64 years).

It is preferable but not mandatory to use the same DTaP product for all doses.

Who should get this vaccine?
All infants should receive DTaP vaccine as part of their routine immunization unless they have a medical reason not to. Persons 10 years and older can receive Tdap vaccine in place of a routine booster dose of adult Td vaccine.

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). Both Tdap vaccines are approved for a single booster dose in their respective age groups, generally as a substitute for one dose of adult formulation tetanus and diphtheria toxoid.

My father never received immunization against pertussis as a child. Should he get immunized as an adult?
Adults or children ages 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. Td will protect you from diphtheria infection as well as tetanus. Tdap vaccine can be substituted for one of these three doses, preferably the first dose for persons 10 years and older to provide protection against pertussis.

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 children 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, especially after the fourth or fifth dose. Other possible reactions may include fussiness, mild fever, loss of appetite, tiredness, and vomiting. The use of the more purified DTaP instead of the whole cell DTP has decreased these mild reactions substantially. Tdap is a new vaccine but trials have shown it to be safe.

What side effects have been reported with this vaccine?
Side effects such as crying for three or more hours (up to about one child out of 1,000 vaccinated) and high fever (about one child in 16,000) were known to have occurred following the whole cell pertussis vaccine in DTP. Now that the acellular pertussis vaccine (DTaP) is used exclusively in the U.S., these types of side effects are seen more rarely (estimated at about 1 in 10,000 doses). More serious reactions, such as seizures, are so rare that it is hard to tell if they are caused by the vaccine. If a child has a medical reason not to receive the pertussis vaccine, they can and should still be vaccinated against just diphtheria and tetanus with DT-pediatric vaccine.

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

How effective is this vaccine?
In general, inactivated vaccines are not as effective in producing immunity as are live vaccines. In studies of acellular pertussis vaccine, children who received three or four doses were 80%-85% less likely to develop pertussis than unvaccinated children. Immunity appears to last for five to 10 years. Tdap vaccine is believed to be similar in effectiveness and duration of immunity as pediatric DTaP vaccines.

Who should NOT receive pertussis vaccine?
People who had a serious allergic reaction to a previous dose of DTaP or Tdap vaccine, or who developed encephalopathy (brain injury) not due to another identifiable cause, should not receive another dose.

Certain rare adverse events following pertussis vaccination usually serve as a precaution against receiving further doses. Such events include a temperature of 105°F or higher, collapse or shock-like state, persistent crying for more than three hours, or convulsions within three days. Even if one of these precautions exists, there may be occasions when the benefit of immunization outweighs the risk (for example, during a community-wide outbreak of pertussis). A person who developed one of these adverse events after pediatric DTaP vaccine may receive Tdap as an adolescent or adult.

A person with a recognized, possible, or potential neurologic condition should delay receiving DTaP or Tdap vaccine until the condition is evaluated, treated, and/or stabilized. Although DTaP vaccine does not cause neurological disorders, receiving the vaccine can cause an already-present underlying condition to show itself.

Persons with a moderate or severe illness should postpone receiving the vaccine until they are well.

Can the vaccine cause pertussis?
No.

Questions and answers about pertussis disease

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