Pertussis Infection in the United States: Role for Vaccination of Adolescents and Adults

Dennis A. Brooks, MD; Richard Clover, MD

Disclosures

J Am Board Fam Med. 2006;19(6):603-611. 

In This Article

Management of Pertussis

Antibiotics and Other Agents

Antibiotic treatment of pertussis infection stops production of pertussis toxin in young infants, which may alter the natural history of the disease. In adolescents and adults, antibiotic therapy must be prescribed early in the disease course to have an impact on duration and severity of symptoms and to lessen the period of communicability.[33] Close contacts of pertussis cases should be given antibiotics to prevent infection and limit transmission. Prophylactic antibiotics should be initiated as soon as possible within 21 days of exposure. Although not fully efficacious, antibiotic prophylaxis has been shown to be a major factor in controlling household transmission and outbreaks. Although fluids and analgesics may provide some symptom relief, no other therapies (eg, system and aerosolized corticosteroids, beta-agonists, and cough suppressants) have proven beneficial.

Pertussis Vaccination of Children

DTaP vaccine, which contains purified, inactivated components of B. pertussis cells (along with tetanus and diphtheria toxoids), has been available in the United States for more than a decade. Since 1997, the CDC recommends DTaP for all doses of the vaccination series for infants and children <7 years of age. The primary immunization series consists of three doses given at 4- to 8-week intervals, beginning at 6 weeks to 2 months of age. A fourth dose is given 6 to 12 months after the third dose. Children who have received all four primary doses before the fourth birthday should receive a fifth (booster) dose before entering school. A fifth dose is not necessary if the fourth dose was administered on or after the fourth birthday.

Point estimates of vaccine efficacy across trials of infants ranged from 80% to 85%.[24] In comparative studies, the acellular pertussis vaccine was significantly more effective than the whole-cell DTP, which is no longer available in the United States. Local and systemic adverse reactions occurred less frequently among infants vaccinated with acellular pertussis vaccine than among those vaccinated with whole-cell pertussis.[34]

Pertussis Vaccination of Adolescents and Adults

The availability of a less reactogenic acellular pertussis vaccine combined with evidence of substantial pertussis infection among adolescents and adults led to reconsideration for the need for acellular pertussis boosters among older subgroups.

Specific formulations of Tdap for adolescents 10 to 18 years, Boostrix® (GlaxoSmithKline), and for adolescents and adults 11 to 64 years, Adacel® (sanofi pasteur), were recently licensed for use in the United States. They contain tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis. In a randomized, controlled, multicenter clinical trial, 10- to 18-year-olds were vaccinated with one dose of Boostrix or a US-licensed Td vaccine.[35] Each subject had completed his or her routine childhood vaccinations against diphtheria, tetanus, and pertussis according to the CDC recommended schedule. Boostrix was comparable to the Td vaccine based on immunogenicity. In both treatment groups, >99.9% of subjects had anti-diphtheria and anti-tetanus concentrations greater than 0.1 IU/mL, indicating seroprotection against these two diseases. In the Boostrix treatment group, anti-pertussis antibodies levels following primary immunization exceeded (by 1.9 to 7.4 times) those observed in infants, in whom efficacy against pertussis disease was previously demonstrated. The overall safety profile was comparable between the Boostrix and Td vaccine groups.

Adacel was evaluated in four principal clinical trials in which 7206 individuals (4185 adolescents and 3021 adults) who had not received tetanus or diphtheria toxoid-containing vaccines within 5 years were enrolled. The trials consisted of one randomized, controlled trial that compared Adacel vaccine to a licensed Td vaccine,[36] one lot consistency trial, and two concomitant administration trials (one with hepatitis B vaccine and one with influenza vaccine). Across trials, a total of 3393 adolescents and 2448 adults received Adacel vaccine and 792 adolescents and 573 adults received Td vaccine. In the largest Adacel trial, the seroprotection rate (of at least 0.1 IU/mL) for tetanus and diphtheria was 99.8% and 100%, respectively.[36] Pertussis antibody geometric mean titers (GMTs) following one dose of Adacel were 2.1- to 5.4-fold higher than those observed among infants following three doses of DTaP. Overall, Adacel vaccine was well tolerated, with local and systemic adverse reactions occurring at similar rates in the Adacel and Td vaccine groups. The ACIP recently revised its recommendations for pertussis vaccination. The immunization schedule now includes a Tdap booster dose for all adolescents at 11 to 12 years of age ( Table 3 ).[37,38] The ACIP also calls for catch-up vaccination of those aged 13 to 18 years who did not receive the Td booster. Finally, because of the importance of controlling pertussis, those in this age range who received the Td booster are encouraged to get the new Tdap vaccine after a suggested 5-year interval. This interval may be shortened to as little as 2 years in the presence of increased risk (eg, during outbreaks or periods of increased pertussis activity in the community).[7]

The ACIP also recommends a single dose of Tdap booster to replace the next scheduled dose of tetanus diphtheria vaccine among persons 19 to 64 years of age. In addition, adults who have or who anticipate having close contact with a vulnerable infant (ie, an infant who has not received two to three doses of DTaP) should receive a single dose of Tdap booster.[39]

In February 2006, the ACIP recommended a single dose of Tdap booster as soon as feasible for health care workers in hospital or ambulatory care settings who have direct patient contact. The Committee stated that priority should be given to vaccination of health care workers with direct contact with infants <12 months of age. Other health care workers should receive a single dose of Tdap booster according to the routine recommendation and interval guidance for use of Tdap among adults.[39]

Widespread administration of Tdap vaccination should have a substantial impact on pertussis. By way of example, adolescent pertussis immunization programs were recently implemented countrywide in Canada, but started earlier in the Northwest Territories and Newfoundland. Following introduction of an adolescent booster dose, pertussis incidence in the Northwest Territories decreased from 7.9 per 100,000 in the late 1990s to 0.2 per 100,000 in 2004.[40] In Newfoundland, no person vaccinated with the Tdap booster has been diagnosed with pertussis to date.[41]

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