In contrast to the humoral immune system, which is the focus of this chapter, the cell-mediated immune system is the branch of the immune system that does not synthesize antibodies. Instead, it is driven by T cells (T lymphocytes) and works by the release of cytokines (chemicals that promote other immune system functions, e.g., inflammatory responses, runny nose) and by phagocytosis (engulfing and destruction of the antigens by the T cells). The cell-mediated immune system is discussed in Chapter 47, because it is the target of immunosuppressant drugs. To varying degrees, these two immune system branches work simultaneously or even interdependently. The humoral immune system is also activated and/or driven partly by cytokines from the cell-mediated immune system.

There are two ways of obtaining immunity to certain infections: active immunization and passive immunization. Each can be an artificial or natural process. In artificial active immunization, the body is clinically exposed to a relatively harmless form of an antigen that does not cause an actual infection. Information about the antigen is then imprinted into the memory of the immune system and the body’s defenses are stimulated to resist any subsequent exposure (by producing antibodies). In contrast, natural active immunization occurs when a person acquires immunity by surviving the disease itself and producing antibodies to the disease-causing organism. Artificial passive immunization involves administration of serum or concentrated immunoglobulins. This directly gives the inoculated person the substance needed to fight off the invading microorganism. This type of immunization bypasses the host’s immune system. Finally, natural passive immunization occurs when antibodies are transferred from the mother to her infant in breast milk or through the bloodstream via the placenta during pregnancy. The major differences between active and passive immunization are summarized in Table 49-1 and are discussed in greater depth in the following sections.

There are specific populations that can benefit from passive immunization but not from active immunization (see Table 49-1). These are people who have been rendered immunodeficient for one reason or another (e.g., by drugs or disease) and who therefore cannot mount an immune response to a toxoid or vaccine injection because their immune system is suppressed. Passive immunizing drugs are also used in people who already have the given disease, especially those with diseases that are rapidly harmful or fatal, such as rabies, tetanus, and hepatitis. Because these diseases can progress rapidly, the body does not have time to mount an adequate immune defense against them before death occurs. The passive immunization of such individuals confers a temporary protection that is usually sufficient to keep the invading organisms from killing them, even though it does not stimulate an antibody response.

The passive immunizing drugs are divided into three groups: antitoxins, immunoglobulins, and snake and spider antivenins. An antitoxin is a purified antiserum that is usually obtained from horses inoculated with the toxin. An immunoglobulin is a concentrated preparation containing predominantly immunoglobulin G and is harvested from a large pool of blood donors. An antivenin, often referred to as antivenom, is an antiserum containing antibodies against a venom, which is a poison secreted by an animal such as a reptile, insect, or other arthropod (e.g., spider). Most antivenins are obtained from animals (usually horses) that have been injected with the particular venom; however, the newer ones are produced by recombinant technology. The serum contains immunoglobulins that can neutralize the toxic effects of the venom.

Vaccines and toxoids are active immunizing drugs that have been developed for the prevention of many illnesses caused by bacteria and their toxins, as well as those caused by various viruses. Antivenins, antitoxins, and immunoglobulins are passive immunizing drugs. Such drugs can inactivate spider and snake venom, bacterial toxins (exotoxins), and potentially lethal viruses. Box 49-1 lists the currently available immunizing drugs. The successful immunization of 95% or more of a population confers protection on the entire population. This is called herd immunity.

Antivenins, also known as antisera, are used to prevent or minimize the effects of poisoning by the venoms of crotalids (rattlesnakes, copperheads, cottonmouths, water moccasins), black widow spiders, and coral snakes, some of which can be lethal. Most healthy adults do not die from the bites of spiders or snakes if they receive prompt and appropriate treatment (i.e., administration of the appropriate antivenin). However, very young children and older persons with health problems are particularly susceptible to the effects of the venom of some of these animals. In either situation, an antivenin is needed to neutralize the venom.

The undesirable effects of the various immunizing drugs can range from mild and transient to serious and even life-threatening and are listed in Table 49-2. The overwhelming majority of adverse effects are minor. Minor reactions can be treated with acetaminophen and rest. More severe reactions, such as fever higher than 103° F (39.4° C), can be treated with acetaminophen and sponge baths. Serum sickness sometimes occurs after repeated injections of equine (horse)–derived immunizing drugs. The signs and symptoms consist of edema of the face, tongue, and throat; rash; urticaria; arthritis; adenopathy; fever; flushing; itching; cough; dyspnea; cyanosis; vomiting; and cardiovascular collapse. Serum sickness is best treated with analgesics, antihistamines, epinephrine, and/or corticosteroids. In these cases, hospitalization may be required.

Any serious or unusual reactions to immunizing drugs need to be reported to the Vaccine Adverse Event Reporting System (VAERS). This is a national vaccine safety surveillance program that is cosponsored by the Food and Drug Administration (FDA) and the CDC. A report can be submitted via the toll-free telephone number 800-822-7967. Alternatively, a reporting form can be printed from the website of either the FDA (http://www.fda.gov) or the CDC (http://www.cdc.gov). These websites have extensive information describing this reporting system and the data collected by it. Such data are used to improve the quality of immunizing drugs and can even be grounds for an FDA recall of biologic drugs whose adverse effects exceed acceptable safety thresholds.

In the early 1980s, in response to vaccine-related injuries, many parents became reluctant to immunize their children against common, and even potentially fatal, childhood illnesses. Increasing numbers of legal actions were also brought by parents of injured children. In 1986, the U.S. Congress passed the Childhood Vaccine Injury Act, which in turn established the National Vaccine Injury Compensation Program (VICP). The purpose was to create a no-fault alternative to the civil tort system, which had driven many vaccine manufacturers out of the field. Serious adverse events following vaccination are very uncommon. The Vaccine Injury Table published by the Health Resources and Services Administration itemizes serious adverse events reported for vaccines that are covered under the VICP, as well as the expected time frame for such events to occur. The first symptom must appear within the listed time frame (Table 49-3) for it to be presumed to be caused by the vaccine. For more information, the reader is referred to www.hrsa.gov/vaccinecompensation/index.html.

TABLE 49-3

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES VACCINE INJURY TABLE

VACCINE	ADVERSE EVENT	TIME INTERVAL
Tetanus toxoid–containing vaccines (e.g., DTaP, Tdap, DTP-Hib, DT, Td, TT)	Anaphylaxis or anaphylactic shock Brachial neuritis	0-4 hr 2-28 days
	Any acute complication or sequela (including death) of above events	NA
Pertussis antigen–containing vaccines (e.g., DTaP, Tdap, DTP, P, DTP-Hib)	Anaphylaxis or anaphylactic shock Encephalopathy (or encephalitis) Any acute complication or sequela (including death) of above events	0-4 hr 0-72 hr NA
Measles, mumps, and rubella virus–containing vaccines in any combination (e.g., MMR, MR, M, R)	Anaphylaxis or anaphylactic shock Encephalopathy (or encephalitis) Any acute complication or sequela (including death) of above events	0-4 hr 5-15 days NA
Rubella virus–containing vaccines (e.g., MMR, MR, R)	Chronic arthritis Any acute complication or sequela (including death) of above event	7-42 days NA
Measles virus–containing vaccines (e.g., MMR, MR, M)	Thrombocytopenic purpura Vaccine-strain measles viral infection in an immunodeficient recipient Any acute complication or sequela (including death) of above events	7-30 days 0-6 mo NA
Polio live virus–containing vaccines (OPV)	Paralytic polio In a nonimmunodeficient recipient In an immunodeficient recipient In a vaccine-associated community case Only gold members can continue reading. Log In or Register to continue Share this: Click to share on Twitter (Opens in new window) Click to share on Facebook (Opens in new window) Related Related posts: Pituitary Drugs Cholinergic-Blocking Drugs Acid-Controlling Drugs Analgesic Drugs Stay updated, free articles. Join our Telegram channel Join Tags: Pharmacology and the Nursing Process May 9, 2017 | Posted by admin in NURSING | Comments Off on Immunizing Drugs and Biochemical Terrorism Full access? Get Clinical Tree Get Clinical Tree app for offline access Get Clinical Tree app for offline access