Immunizations

Description

Alternative Names

Diptheria, Tetanus, and Pertussis

Diphtheria. Diphtheria is caused by a bacterium, Corynebacterium diphtheriae, which can occur as either a toxic or nontoxic strain. When only the skin is involved, it is known as cutaneous diphtheria, and is likely to be a nontoxic strain. When the toxic strain affects the mucus linings in the body, such as the throat, diphtheria becomes life threatening. In the first quarter of the twentieth century diphtheria infected 200,000 people every year and killed between 5% and 10% of them, mostly the very young and very old. Because of immunizations, only one case was reported in 2000.

Tetanus. Tetanus is a disease marked by severe muscular contractions and convulsions brought on by a powerful toxin secreted by the bacterium, Clostridium tetani. The bacterium is anaerobic; that is, it lives without oxygen. People become infected by this dangerous bacterium through wounds in the skin. It is fatal in 15% to 40% of cases. Only 35 cases were reported in the US in 2000, mostly in adults. However one case occurred in a 12-year-old whose parents refused to vaccinate him.

Pertussis. Pertussis (whooping cough) was a very common childhood illness throughout the first half of the century. The disease is very easily spread from one person to another, and it is most severe in babies. Although immunizations caused a decline in cases to only 1,700 in the US in 1980, the incidence has risen recently, with almost 30,000 cases reported between 1997 and 2000 (17 infants died of the disease in 2000). Many more cases are reported worldwide. Nearly half of pertussis cases now occur in people 10 years of age or older, perhaps due to waning immunity in adolescents and adults. Such cases may be greatly underreported. One study suggested that as many as 25% of adults who see a doctor for persistent cough may actually have pertussis, but it may go undiagnosed because symptoms are usually mild and adults are unlikely to have the classic whooping cough. This is of some concern, because such adults may unknowingly infect unvaccinated children. The younger the patient, the higher the risk for severe complications, including pneumonia, seizures, and even death. Children younger than six months are at particular risk because even with vaccination, protection is incomplete.

Vaccinations for Diphtheria, Tetanus, and Pertussis

The Initial Vaccination. Diphtheria, tetanus, and pertussis are very different disorders, but a combination injection has been routinely given to children since the 1940s. The standard vaccine is DTaP, which uses a form of the pertussis component known as acellular pertussis that consists of a single weakened toxoid. (The older vaccine, DTP, includes a pertussis vaccine that contains multiple toxins against different variants of the disease. It has more severe side effects than DTaP.)

The Booster. Protection against diphtheria and tetanus from the vaccine lasts about 10 years. At that point a booster may be given against tetanus and diphtheria (Td). The Td vaccine contains the standard dose against tetanus and a less potent one against diphtheria and does not contain the pertussis component.

The pertussis component of the vaccination is usually not given to older children and adults because whooping cough is less severe as people get older while the side effects of the vaccine may be more severe. Some experts are considering recommending continuing immunization against whooping cough in all older people who might become reinfected and therefore threaten unvaccinated children. The new acellular pertussis vaccine may make such adult boosters feasible.

DTaP Schedule in Childhood. The DTaP vaccine should be given to all children less than seven years old. In general, the vaccinations are given as follows:

• Infants receive a series of three vaccinations at two, four, and six months of age. (Physicians may delay a vaccination in infants with suspected neurologic problems until their neurologic situation is clarified, but no later than their first birthday). Children with neurologic problems that have been corrected can be vaccinated.
• A fourth dose is given between 15 and 18 months. (Infants at higher risk, such as those exposed to an outbreak of pertussis, may be given this vaccination earlier.) Of note, children who receive their third shot late in the schedule are at higher risk for skipping the fourth dose than children who were on schedule. Parents should be sure to adhere to a schedule that includes the fourth shot, even if they were late on the third.
• A fifth dose is given at four to six years. This fifth shot now usually includes a vaccine against Haemophilus influenzae as well.
• Children between the ages of eleven and fifteen years old should receive a tetanus and diphtheria (Td) booster shot.

If a child has a moderate or severe current or recent fever-related illness, vaccinations should be postponed until after recovery. Colds or other mild respiratory infections are no cause for delay. Parents should not be unduly concerned if the interval between shots is longer than that recommended. The immunity from any previous vaccinations persists, and the physician does not have to start a new series from scratch.

DTP Schedule in Adulthood. All vaccinated adults should have a Td booster at least every 10 years throughout their lifetimes. (A 2002 study reported that less than half of adult Americans ages 20 and older were protected against both tetanus and diphtheria, and immunity rates were even lower in those over 70. The results indicate that many people are not getting routine boosters.)

Other recommendations for adults are as follows:

Adults who did not receive the primary childhood vaccinations should have a series of three Td vaccinations. The first two doses should be given at least a month apart and the third dose given six to 12 months after the second.

Unvaccinated pregnant women should receive two doses of Td, properly spaced, and previously vaccinated women should have a booster.

Preventing Tetanus in Individuals with Wounds. Wounds that put patients at highest risk for tetanus are puncture wounds or wounds contaminated with dirt, feces, or saliva. However, any patient who requires medical care for any wound is a candidate for tetanus immunity.

Some considerations for tetanus vaccinations in wounded people are as follows:

• A booster is needed if the last shot was five or more years before the injury.
• Children under seven are usually given DTP if they are not fully vaccinated.
• Most individuals are given the Td vaccination if they have been vaccinated.
• Older patients who had experienced an allergic response to a previous tetanus booster may be given the tetanus immune globulin (TIG).

Side Effects of Diphtheria-Tetanus-Pertussis Vaccines

Allergic Reactions. In rare cases, people may be allergic to the DTP vaccine. Parents should tell their doctor if their children have any allergies. The DTaP vaccine may pose a slightly higher risk for an allergic reaction than the DTP. Children who have severe responses should not be given further vaccinations. A rash that occurs after a dose of DTP is of little consequence. In fact, it does not usually indicate an allergic response but only a temporary immune reaction and does not usually recur with subsequent shots. It should be noted that no deaths have been reported from allergic reactions, even severe (anaphylactic) ones, to the DTP vaccine.

Pain and Swelling at the Injection Site. Children may feel pain at the injection site. In some cases, a small lump may persist at the site for several weeks. Placing a clean, cool washcloth over any swollen, hot, or red area can help. Children should not be covered or wrapped tightly in clothes or blankets.

The risk for swelling, including of the whole arm or leg, increases with subsequent injections, particularly the fourth and fifth doses. If possible, parents should request that their children receive the same vaccine brand each time to help reduce the risk of side effects.

Fever and Other Symptoms. A child may develop a mild fever, irritability, drowsiness, and loss of appetite after a shot.

The following remedies may be helpful:

• Acetaminophen (Children's Tylenol and other brands) and a sponge bath in lukewarm, not cold, water may help relieve fever and pain.
• The physician may suggest that children who have had previous high fevers or other reactions to the shot be given acetaminophen at the time of the vaccination and every four hours afterward for 24 hours. (The doctor will determine the dosage according to the weight of the child.)
• Children should never be given aspirin.

Fevers that should cause notice are the following:

• The older DTP vaccine posed some risk for fever-related seizures on the day of vaccination. The newer DTaP has significantly reduced this side effect. Any very high fever in children (over 105 degrees) that causes convulsions should be reported immediately to the physician. Although frightening, such fever-related seizures are uncommon and rarely have any long-term effect, and a recurrence after a subsequent vaccination is very unlikely.
• A new fever that develops 24 hours after the vaccination, a fever that persists for longer than 24 hours, or seizures without fever are most likely due to other causes.

Hypotonic-Hyporesponsive Episode (HHE). HHE is an uncommon response to the pertussis component and occurs within 48 hours of the injection in children under two. The child usually starts out feverish and irritable and then becomes pale, limp, and unresponsive. Breathing is shallow and the child's skin may turn bluish. The reaction lasts an average of six hours and, although it is frightening, virtually all children return to normal. This side effect is less common since the introduction of the DTaP vaccine, but it can still occur.

Neurologic Effects in Pertussis Component. Of concern have been a few reports of permanent neurologic abnormalities that have occurred after children have been vaccinated. Such reports include attention deficit disorder, learning disorders, autism, brain damage (encephalopathy), and even death.

It is well known that the diphtheria and tetanus components have no adverse neurologic effects, so some people suspect the pertussis component. Now, many major studies, including an important statistically sound analysis in 2002, found no causal relationship between neurologic problems and the pertussis vaccination. In fact, one study indicated that children who received pertussis vaccine had fewer problems in school than those who were not vaccinated, regardless of family income levels. Studies on the newer DTaP have reported no safety concerns to date.

There may be some exceptions. Studies now suggest that in cases where neurologic problems have been strongly linked to the vaccination, high fevers--not immunization--are responsible. Children with known neurologic abnormalities may also be at risk for an outbreak of symptoms two or three days after the vaccination. Such a temporary worsening of their disease rarely poses a danger to the child. (Some experts suggest that children who have new neurologic events following their shot may already have a preexisting impairment, such as epilepsy, which is revealed--but not caused--by the vaccine.) A 2003 study did report an association between thimerosal, a preservative previously used in DTaP vaccines and a higher risk for problems in neurologic development, including autism and speech problems. More evidence is needed to confirm this. (Thimerosal has now been removed from the vaccine.) In summary, there is no proof to date that the pertussis vaccine caused these neurologic events, which, in any case, are so infrequent as to be nearly unmeasurable.

Important Note: Unwarranted fears of side effects from vaccinations can be dangerous. In England such fears have caused a significant decline in immunization rates since the 1970s. Outbreaks of whooping cough have occurred as a result, causing a number of deaths and brain damage in many children. Small babies are particularly endangered if they become infected from older unvaccinated children (who usually have a mild disease).