DTP vaccine confers immunity to diphtheria , tetanus , and pertussis. The vaccine used in the United States is actually multiple diphtheria and tetanus toxoids combined with acellular pertussis (DTaP). The original vaccine, which as of 2004 was still used in other parts of the world, contains whole cells of Bordatella pertussis, the organism that causes pertussis, better known as whooping cough . The whole cell vaccine is more likely to cause adverse effects and does not provide any greater immunity.
DTP vaccine conveys immunity to three different infectious diseases:
- Diphtheria is a potentially fatal disease that usually involves the nose, throat, and air passages, but may also infect the skin. Its most striking feature is the formation of a grayish membrane covering the tonsils and upper part of the throat. It is caused by Corynebacterium diphtheriae. Routine vaccination has almost eradicated diphtheria from the United States, but it is still seen in many parts of the world.
- Tetanus, sometimes called lockjaw, is a disease caused by the toxin of Clostridium tetani. The disease affects the central nervous system and causes painful muscle contractions. Food is not given by mouth to those with muscle spasm but may be given via nasogastric tube or intravenously. Tetanus is often fatal.
- Pertussis, also called whooping cough, is a respiratory disease caused by Bordatella pertussis. The name comes from a typical cough which starts with a deep inhalation, followed by a series of quick, short coughs that continues until the air is expelled from the lungs, and ends with a long shrill, whooping inhalation. Pertussis is very contagious and usually affects young children.
Diphtheria and tetanus toxoids and acellular pertussis, taken together, provides immunity against diphtheria, tetanus, and whooping cough. The vaccine is normally given to children somewhere between the ages of two months and seven years of age (prior to their seventh birthday). Because these diseases can pose a severe problem in early childhood, the shots should be given as early in life as possible.
DTP vaccine should not be given to children seven years of age or older. Moreover, children who are allergic to any component of the vaccine should not receive the drug. Because there are several different brands on the market, some children may be allergic to one brand and not to another. Because some of the bacterial cultures are grown in beef broth, the injections may be inadvisable for children who are allergic to beef. Children who have an allergic reaction after the first shot should be referred to an allergist before continuing with the DTP injections. Children who within a week after vaccination develop encephalopathy that cannot be traced to any other cause should not receive further injections. These children may be treated with DT (diphtheria-tetanus) vaccine. Also, DTP vaccine should be used with caution in patients who are receiving anticoagulant therapy. If a patient with a history of fevers and febrile convulsions is to be given DTP, the patient should receive acetaminophen at the time of the injection and for the following 24 hours.
DPT vaccine has been associated with allergic reactions and with encephalopathy, both of which are rare but severe conditions. Other risks are common but minor:
- redness, irritation, and itching at injection site
- loss of appetite
Because DTP vaccine is injected deep into the muscle, it should be given with care to patients receiving anticoagulant therapy. Also, immunosuppressant drugs, including steroids and cancer drugs, may reduce the ability of the body to produce antibodies in response to DTP vaccine.
DTP is given in a series of four doses. Usually, the doses are given at two, four, and six months of age and at 17 to 20 months of age. While the customary age for the first dose is two months, it may be given as early as six weeks of age and up to the seventh birthday. The interval between the third and fourth dose should be at least six months.
Although there have been warnings about severe, even fatal reactions to DTP vaccine, these reactions were seen in about one in 140,000 cases with whole cell DTP. The risk with DTaP is considerably lower. Children who had seizures due to the vaccine normally made a full recovery with no neurologic problems afterward. Five well-designed studies failed to show a link between DTP vaccine and any chronic nerve conditions.
The most serious risk of DTaP vaccine is a severe allergic reaction. These reactions, which also occur in response to other vaccines, are potentially fatal. Pre-term infants should be vaccinated according to their chronological age from birth. Interruption of the recommended schedule with a delay between doses should not interfere with the final immunity achieved. There is no need to start the series over again, regardless of the time between doses.
Encephalopathy —Any abnormality in the structure or function of brain tissues.
Larynx —Also known as the voice box, the larynx is the part of the airway that lies between the pharynx and the trachea. It is composed of cartilage that contains the apparatus for voice production–the vocal cords and the muscles and ligaments that move the cords.
Toxin —A poisonous substance usually produced by a microorganism or plant.
See also Vaccination.
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Samuel Uretsky, PharmD