Diphtheria, Tetanus, and Pertussis

Description

Diphtheria is an acute bacterial disease involving primarily the tonsils, pharynx, larynx, nose, skin, and occasionally other mucous membranes. The characteristic lesion is marked by a patch or patches of an adherent grayish membrane with a surrounding inflammation.

Tetanus is an acute disease characterized by muscle rigidity and painful spasms, often starting in the muscles of the jaw and neck. The disease is caused by neurotoxin produced by anaerobic tetanus bacilli growing in contaminated wounds. Lesions that are considered “tetanus prone” are wounds contaminated with dirt, feces or saliva, deep wounds, or those with necrotic tissue. However, tetanus has been associated with apparently clean superficial wounds, surgical procedures, insect bites, dental infections, chronic sores and infections, and intravenous drug use. In 5%–10% of reported cases in the United States, no antecedent wound was identified.

Pertussis is an acute bacterial disease involving the respiratory tract, characterized by prolonged paroxysmal coughing. Persons in all age groups can be infected. Complications and deaths from pertussis are most common among infants.

Occurrence

Diphtheria remains a serious disease throughout much of the world. In particular, large outbreaks of diphtheria occurred in the 1990s throughout Russia and the independent countries of the former Soviet Union. Most life-threatening cases occurred in unvaccinated or inadequately immunized persons. Children traveling to countries where the risk of diphtheria is high should be vaccinated according to the Recommended Childhood Immunization Schedule. Travelers to disease-endemic areas may be at increased risk for exposure to toxigenic strains of Corynebacterium diphtheriae when travel is for extended periods, when there is contact with children, or when conditions are crowded or foster sharing of respiratory secretions. Countries with endemic diphtheria include Africa – Algeria, Egypt, and the countries in sub-Saharan region; Americas – Brazil, Dominican Republic, Ecuador, and Haiti; Asia/Oceania – Afghanistan, Bangladesh, Cambodia, China, India, Indonesia, Iran, Iraq, Laos, Mongolia, Burma (Myanmar), Nepal, Pakistan, Philippines, Syria, Thailand, Turkey, Vietnam, and Yemen; and Europe – Albania and all countries of the former Soviet Union. Control measures may have been implemented, but a risk of diphtheria remains in all these areas.

Tetanus is a global health problem since Clostridium tetani spores are ubiquitous. The disease occurs almost exclusively in persons who are unvaccinated or inadequately immunized.

Pertussis is severe primarily in children; it is often associated with complications and has a relatively high case-fatality ratio in unvaccinated infants. Pertussis can also occur in adolescents and adults after immunity from vaccines has waned. Pertussis is highly communicable and is common, particularly in countries where vaccination is not generally provided.

When pertussis is highly suspected in a patient, chemoprophylaxis of all close contacts and high-risk contacts with erythromycin is recommended regardless of their age and vaccination status. Initiating chemoprophylaxis 3 weeks or more after exposure has limited benefit for the contacts. However, chemoprophylaxis should be considered for high-risk contacts up to 6 weeks after exposure.

Risk for Travelers

Diphtheria and pertussis are more frequent in parts of the world where vaccination levels are low. Tetanus can occur anywhere in the world in unvaccinated persons.

Prevention

Vaccine

Immunizations for Infants and Children < 7 Years of Age

Simultaneous immunization against diphtheria, tetanus, and pertussis during infancy (see Tables 7–1 and 7–2) is recommended. Combination vaccines contain diphtheria and tetanus toxoids and either whole-cell pertussis antigens (DTwP) or acellular pertussis antigens (DtaP). Neither DTwP nor DTaP pertussis vaccine is licensed for persons 7or more years of age. DTwP vaccine is no longer available for use in the United States. Pertussis vaccination is not recommended after a child's seventh birthday.

Three brands of DTaP currently are approved for use and are available in the United States. Each brand contains a different number and concentration of pertussis antigen. Each is safer than DTwP vaccine. The Advisory Committee on Immunization Practices (ACIP) and the American Academy of Pediatrics indicate no preferences for one brand over another.

Primary immunization for infants and children up to the seventh birthday consists of four doses of DTaP vaccine (Table 7–1). The first dose is typically given when an infant is 2 months of age. The first three doses should be given at 4- to 8-week intervals, with the fourth dose given when the infant is 15–18 months of age. A fifth (booster) dose is recommended when the child is 4–6 years of age. The fifth dose is not necessary if the fourth dose in the primary series was given after the child's fourth birthday.

Three—and preferably four—doses of DTaP are necessary for protection against diphtheria and pertussis. Travelers should be advised to complete as many doses as possible of the primary series before traveling. If an accelerated schedule is required to complete the series of DtaP vaccine, the schedule may be started as soon as the infant is 6 weeks of age, with the second and third doses given 4 weeks after each preceding dose (see Table 7–1). The fourth dose should not be given before the child is 12 months of age and should be separated from the third dose by at least 6 months. The fifth (booster) dose should not be given before the child is 4 years of age. Interruption of the recommended schedule or delay in doses does not lead to a reduction in the level of immunity reached on completion of the primary series. There is no need to restart a series regardless of the time that has elapsed between doses.

There are limited data describing the safety, immunogenicity, and efficacy of using DTaP vaccines from different manufacturers for successive doses of the primary or booster vaccination series (“mix and match”). Whenever possible, the same brand of DTaP vaccine should be used for all doses of the vaccination series. To avoid delays in vaccination, any licensed DTaP vaccine may be used to continue or complete the vaccination series, if the type of vaccine previously administered is not known or the type of vaccine used for earlier doses is not available. A pertussis vaccination series begun with DTwP may be completed with DTaP.

Infants and children inadequately immunized for their age should be brought up to date before travel. For infants and children <7 years of age with a contraindication to the pertussis component of DTaP, diphtheria-tetanus (DT) should be used (Table 7–1).

Immunizations for Children 7 or More Years of Age, Adolescents, and Adults

Children 7 or more years of age, adolescents, and adults should receive the adult formulation of tetanus and diphtheria toxoids (Td) (Table 7–1) whenever either tetanus or diphtheria toxoid is indicated. Anyone 7 or more years of age who has not received a primary series against tetanus and diphtheria should receive three doses of Td; the first two doses should be given 4–8 weeks apart and the third dose 6–12 months after the second. Two doses of Td received at intervals of at least 4 weeks can provide some protection, but a single dose is of little benefit. In the rare instance when administration of the third dose following a 6- to 12-month interval cannot be ensured, the third Td dose can be given 4–8 weeks after the second dose to complete the primary series. Anyone for whom primary tetanus and diphtheria vaccination is uncertain should be considered unvaccinated and should receive the three-dose series. Anyone who has received only one or two prior doses of tetanus and diphtheria toxoids should receive additional doses to complete the three-dose series. The first booster dose of Td should be given when the child is 11 or 12 years of age if at least 5 years has elapsed since the last dose of DTaP or pediatric DT. Thereafter, routine booster doses of Td should be given every 10 years.

Adverse Reactions

Local reactions (generally erythema and induration with or without tenderness) are common after the administration of vaccines containing diphtheria, tetanus, and pertussis antigens. Mild systemic reactions such as fever, drowsiness, fretfulness, and low-grade fever can occur after vaccination with either DTwP or DTaP. However, even mild reactions following the first four doses are less common among children who receive DTaP. For example, fever >38.3° C (>101° F) is reported in 3%–5% of DTaP recipients, compared with 16% of DTwP recipients. These reactions are self-limited and can be managed with symptomatic treatment of acetaminophen or ibuprofen. Reports of moderate to severe systemic events (e.g., fever 40.5° C or higher [105° F or higher], febrile seizures, persistent crying lasting 3 hours or more, and hypotonic-hyporesponsive episodes) have been uncommon after administration of DTaP, and they have occurred less frequently among children administered DTaP than those administered DTP.

Anaphylactic and other serious adverse reactions are rare after receipt of preparations containing diphtheria, tetanus or pertussis components, or a combination of these. Arthus-type hypersensitivity reactions, characterized by severe local reactions, have been reported in adults who received frequent boosters of tetanus or diphtheria toxoids. The rates of local reactions, fever, and other common systemic symptoms following receipt of DTaP are lower than those following DTwP vaccination.

Precautions and Contraindications

A severe allergic reaction to a prior dose of vaccine or vaccine component is a contraindication to further vaccination with DTaP, DT, or adult Td. Encephalopathy not due to another identifiable cause within 7 days of vaccination is a contraindication to further vaccination with a pertussis-containing vaccine.

Moderate or severe acute illness can be a contraindication to vaccination. Anyone with mild illnesses, such as otitis media or upper respiratory infection, should be vaccinated. Anyone for whom vaccination is deferred because of moderate or severe acute illness should be vaccinated when the condition improves.

Certain infrequent adverse events following pertussis vaccination generally contraindicate subsequent doses of pertussis vaccine. These adverse events include temperature >40.5° C (>105° F) not resulting from another identifiable cause; collapse or a shock-like state (hypotonic-hyporesponsive episode) or persistent, inconsolable crying lasting >3 hours and occurring within 48 hours of vaccination (applicable to infants and children); and convulsions with or without fever occurring within 3 days of vaccination. In certain circumstances (e.g., during a communitywide outbreak of pertussis), the benefit of vaccination may outweigh the risk, even if one of the four precautionary adverse events occurred following a previous dose. Under these circumstances, one or more additional doses of pertussis vaccine may be considered. DTaP should be used in these circumstances.

DTaP vaccine should NOT be substituted in infants and children who have a valid contraindication to DTwP vaccine. If a valid contraindication or precaution exists, DT should be used for the remaining doses in the schedule.

Neurologic conditions characterized by changing developmental findings are considered contraindications to receipt of pertussis vaccine. Such disorders include uncontrolled epilepsy, infantile spasms, and progressive encephalopathy. For an infant who, because of perinatal complications or other conditions, is thought to be at an increased risk for latent onset of central nervous system disorders, immunization with DTaP or DT should be delayed until further observation and study have clarified the infant's neurologic status. The decision whether to commence immunization with DTaP or with DT should be made no later than an infant's first birthday. Infants and children with stable neurologic conditions such as cerebral palsy or well-controlled seizures should be vaccinated. The occurrence of a single seizure (not temporally associated with DTaP) does not contraindicate DTaP vaccination, particularly if the seizure can be satisfactorily explained. Parents of infants and children with personal or family histories of convulsion should be informed of the increased risk for simple febrile seizures following immunization. Acetaminophen (15 mg/kg, every 4 hours for 24 hours) should be given to infants and children with such histories to reduce the possibility of postvaccination fever. Infants and children who have received more than one dose of DTaP and who have a neurologic disorder (e.g., a seizure) not temporally associated with the vaccination, but before the next scheduled dose, should have their neurologic status evaluated and clarified before a subsequent dose of DTaP is given.

— Kris Bisgard, Chima Ohuabunwo, Martha Roper