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Pertussis Vaccine

Written by Subject: Vaccines and Vaccinations
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 vaccines available in the U.S. All three vaccines are equally effective and safe, and are given on the same schedule at two, four, six, 15-18 months, and 4-6 years. DTaP is also part of four childhood combination vaccines that include other vaccines (e.g., IPV, Hib, HepB). Two companies produce the Tdap vaccines that are approved for use in adolescents and adults through the age of 64 years.

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 should receive Tdap vaccine in place of a one-time routine booster dose of adult Td vaccine.

Women who are pregnant or who have recently given birth should be given a one-time dose of Tdap to protect their newborn. Because other adults who have close contact with infants also pose a risk of spreading pertussis to the infant, family members and other caregivers of new infants should receive Tdap vaccine.

Tdap vaccine is also recommended for healthcare personnel in hospitals and ambulatory care settings who have direct patient contact, especially those working with infants, regardless of when they received their previous dose of 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 dose, or booster, is recommended at 4-6 years of age, unless the fourth dose was given late (after the fourth birthday). All adolescents and adults younger than age 65 years should receive a one-time dose of Tdap.

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?
About 20%-40% of children have some local reaction such as pain, redness, or swelling after the first three doses of DTaP. Such local reactions seem to be more frequent after the fourth and/or fifth doses. A temperature of 101° F or higher is reported in 3%-5% of DTaP recipients. Less common reactions (e.g., persistent crying, higher fever, febrile seizure) are rare and generally occur in fewer than 1 in 10,000 doses. If a child has a medical reason not to receive the pertussis vaccine, they can and should still be vaccinated against diphtheria and tetanus with DT (pediatric) vaccine.

The most frequently reported side effects following vaccination with Tdap are 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. 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?

Can a pregnant woman receive Tdap vaccine?
Tdap is not contraindicated during pregnancy. It should be administered to a pregnant woman who is in contact with an infant younger than age 12 months, is in an outbreak setting, or is a healthcare provider who sees children. If there is no risk to the pregnant woman of acquiring or transmitting pertussis, the CDC's Advisory Committee on Immunization Practices recommends that Tdap vaccination be deferred until the immediate postpartum period. The new mother should receive Tdap before hospital discharge, even if she is breastfeeding.

Questions and answers about pertussis disease