Department of Public Health
- Glossary List

Term Definition
ACELLULAR VACCINE Vaccine containing partial cellular material as opposed to complete cells.
ACTIVE IMMUNITY The production of antibodies against a specific disease by the immune system. Active immunity can be acquired in two ways, either by contracting the disease or through vaccination. Active immunity is usually permanent, meaning an individual is protected from the disease for the duration of their lives.
ACUTE A short-term, intense health effect.
ADJUVANT A substance (e.g. aluminum salt) that is added during production to increase the body's immune response to a vaccine.
ADVERSE EVENTS Undesirable experiences occurring after immunization that may or may not be related to the vaccine.
ADVISORY COMMITTEE ON IMMUNIZATION PRACTICES (ACIP A panel of 10 experts who make recommendations on the use of vaccines in the United States. The panel is advised on current issues by representatives from the Centers for Disease Control and Prevention, Food and Drug Administration, National Institutes of Health, American Academy of Pediatrics, American Academy of Family Physicians, American Medical Association and others. The recommendations of the ACIP guide immunization practice at the federal, state and local level.
ALLERGY A condition in which the body has an exaggerated immune response to a substance, e.g. food or drug. Also known as hypersensitivity or an allergic reaction.
ANAPHYLAXIS An immediate and severe allergic reaction to a substance, e.g. food or drug. Symptoms of anaphylaxis include breathing difficulties, loss of consciousness, and a drop in blood pressure. This condition can be fatal and requires immediate medical attention.
ANTHRAX An acute infectious disease caused by the spore-forming bacterium Bacillus anthracis. Anthrax most commonly occurs in hoofed mammals and can also infect humans.
ANTIBODY A protein found in the blood that is produced in response to foreign substances, e.g. bacteria or viruses, invading the body. Antibodies protect the body from disease by binding to these organisms and destroying them.
ANTIGEN Foreign substance e.g. bacteria or virus, in the body that is capable of causing disease. The presence of antigens in the body triggers an immune response, usually the production of antibodies and cytotoxic T cells.
ASSOCIATION The degree to which the occurrence of two variables or events are linked. Association describes a situation where the likelihood of one event occurring depends on the presence of another event or variable. However, an association between two variables does not necessarily imply a cause and effect relationship. The term association and relationship are often used interchangeably. See causal association.
BRACHIAL NEURITIS Inflammation of nerves in the arm causing muscle weakness and pain.
BREAKTHROUGH INFECTION Development of a disease despite a person's having responded to a vaccine.
CAUSAL ASSOCIATION The presence or absence of a variable, e.g. smoking, is responsible for an increase or decrease in another variable, e.g. cancer. A change in exposure leads to a change in the outcome of interest.
CHRONIC A disease or health condition that lasts for a long period of time, e.g. chronic hepatitis B.
CHRONIC CARRIER Person who remains infected with a disease agent and therefore may be able to pass the disease agent to persons they come into contact with. Chronic carriers may or may not exhibit disease symptoms.
COMBINATION VACCINE Two or more vaccines administered in a single injection in order to reduce the number of shots given, e.g. MMR (measles, mumps, rubella) vaccine.
CONJUGATE VACCINE The joining together of two compounds (usually a protein and a polysaccharide) to increase a vaccine's effectiveness.
DIPHTHERIA Can cause a thick covering in the back of the throat which may cause difficulty breathing. It may also lead to suffocation, paralysis, and heart failure. (pink book chapter on diphtheria) (view photo)
EFFICACY A measure used to describe how good a vaccine is at preventing the targeted disease.
EPIDEMIC The occurrence of disease within a specific geographical area or population that is in excess of what is normally expected.
EPIDEMIOLOGIC STUDIES Studies of how disease is distributed in populations and of the factors that influence or determine this distribution.
GUILLAIN-BARRE SYNDROME (GBS): A rare neurological disease characterized by loss of reflexes and temporary paralysis. Symptoms include weakness, numbness, tingling and increased sensitivity that spreads over the body. Muscle paralysis starts in the feet and legs and moves upwards to the arms and hands. Sometimes paralysis can result in the respiratory muscles causing breathing difficulties. Symptoms usually appear over the course of one day and may continue to progress for 3 or 4 days up to 3 or 4 weeks. Recovery begins within 2-4 weeks after the progression stops. While most patients recover, approximately 15%-20% experience persistent symptoms. GBS is fatal in 5% of cases.
HAEMOPHILUS INFLUENZAE TYPE B Abbreviated as Hib. Is a cause of meningitis that can result in hearing loss, seizures, or mental retardation. (pink book chapter on Hib) (view photo)
HEPATITIS Hepatitis A & B infections cause loss of appetite, nausea, vomiting, jaundice (yellowing of the eyes and skin), liver failure, and death. Hepatitis B can also lead to liver cancer. A blood test is used to tell which type of hepatitis a person has. (pink book chapters on hep A and hep B) (view photos)
HERD IMMUNITY Having a large percentage of the population vaccinated in order to prevent the spread of certain infectious diseases. Even individuals not vaccinated (such as newborns and those with chronic illnesses) are offered some protection because the disease has little opportunity to spread within the community.
HERPES ZOSTER A disease characterized by painful skin lesions that occur mainly on the trunk (back and stomach) of the body but which can also develop on the face and in the mouth. Complications include headache, vomiting, fever and meningitis. Recovery may take up to 5 weeks. Herpes Zoster is caused by the same virus that is responsible for chickenpox. Most people are exposed to this virus during childhood. After the primary infection (chickenpox), the virus becomes dormant, or inactivated. In some people the virus reactivates years, or even decades, later and causes herpes zoster. Also known as the shingles.
HIVES The eruption of red marks on the skin that are usually accompanied by itching. This condition can be caused by an allergy (e.g. to food or drugs), stress, infection or physical agents (e.g. heat or cold). Also known as uticaria.
HUMAN PAPILLOMAVIRUS More than 100 types of HPV exist; more than 30 types can infect the genital area. Genital HPV is the most common sexually transmitted infection in the United States; an estimated 6.2 million persons are newly infected every year. Although the majority of infections cause no clinical symptoms and are self-limited, persistent infection with high-risk types can cause cervical cancer in women. HPV infection also is the cause of genital warts and is associated with other genital and anal cancers.
HYPERSENSITIVITY A condition in which the body has an exaggerated immune response to a substance, e.g. food or drug. Also known as an allergy.
IMMUNE GLOBULIN A protein found in the blood that fights infection. Also known as gamma globulin.
IMMUNE RESPONSE Collective and coordinated response by the molecules and cells of the immune system that result in the elimination of naturally acquired disease-causing agents. This response also can be triggered by vaccination leading to immune protection against specific diseases.
IMMUNE SYSTEM Tissues, cells, and molecules found throughout the body that work together in a coordinated fashion to eliminate and prevent infections.
IMMUNITY Protection against a disease. There are two types of immunity: active and passive. Active immunity is protection that is produced by the person's own immune system; this type of immunity is usually permanent. Passive immunity is protection by products produced by an animal or human and transferred to another human, usually by injection. Passive immunity often provides effective protection, but this protection wanes (disappears) over time, usually a few weeks or months.
IMMUNIZATION The process by which a person or animal becomes protected against a disease. This term is often used interchangeably with vaccination or inoculation.
IMMUNOGENICITY The ability to produce a detectable immune response.
IMMUNOSUPPRESSED When the immune system is unable to protect the body from disease. This condition can be caused by disease (like HIV infection or cancer) or by certain drugs (like those used in chemotherapy). Also known as immunocompromised.
INACTIVATED VACCINE A vaccine made from viruses and bacteria that have been killed through physical or chemical processes; these killed organisms cannot cause disease. Inactivated vaccines always require multiple doses.
INCIDENCE The number of new disease cases reported in a population over a certain period of time.
INFLUENZA Highly contagious viral infection of the nose, throat, and lungs. Commonly known as the flu, this seasonal disease can be fatal to the aged, immunocompromised, and infants. (pink book chapter on influenza) (view photo)
LIVE ATTENUATED VACCINE Vaccine in which a live virus or bacteria is weakened through chemical or physical processes in order to produce an immune response without causing the severe effects of the disease. Measles, mumps, rubella, varicella, polio, and yellow fever are live attenuated vaccines.
MEASLES Causes a rash, fever, cough, and can lead to pneumonia, brain damage, hearing loss, and death. (pink book chapter on measles) (view photo)
MUMPS Causes fever and swollen, painful glands under the jaw. It can lead to swelling of the brain and hearing loss. (pink book chapter on mumps) (view photo)
PANDEMIC An epidemic occurring over a very large area.
PATHOGENS Organisms, e.g. bacteria, viruses, parasites, and fungi, that cause disease.
PERTUSSIS Also known as whooping cough. Can cause coughing and choking that makes it hard to breathe. The cough can last for many weeks and result in brain damage or death, especially in infants under 1 year of age. (pink book chapter on pertussis) (view photo)
PNEUMOCOCCAL DISEASE Bacterial disease that causes pneumonia, bacteremia, sinusitus, meningitis, and severe ear infections. The disease is most common in children less than 2 years of age and adults over 40 years of age, and occurs more often in males than females at all ages. (pink book chapter on pneumococcal disease) (view photo)
POLIO A sometimes crippling disease that can also cause paralysis and death. (pink book chapter on polio) (view photo)
POLYSACCHARIDE VACCINE Vaccines that are composed of long chains of sugar molecules that resemble the surface of certain types of bacteria. Polysaccharide vaccines are available for pneumococcal disease and meningococcal disease.
PRESERVATIVE An additive that protects vaccine against contamination or spoilage.
PREVALENCE The number of disease cases (new and existing) within a population over a given period of time.
RECOMBINANT Of or resulting from new combinations of genetic material or cells; the genetic material produced when segments of DNA from different sources are joined to produce recombinant DNA.
RELATIVE RISK The ratio of the risk of disease in persons exposed to a risk factor compared to the risk of disease in persons not exposed to the risk factor.
RISK The likelihood that an individual will experience a certain event.
ROTAVIRUS A group of viruses that cause diarrhea in children.
RUBELLA Also known as German measles. It is usually a mild disease in children. However, infected children can spread the disease to pregnant women. Babies born to women with rubella can have severe birth defects. (pink book chapter on rubella) (view photo)
SHINGLES A disease characterized by painful skin lesions that occur mainly on the trunk (back and stomach) of the body but which can also develop on the face and in the mouth. Complications include headache, vomiting, fever, and meningitis. Recovery make take up to five weeks. Shingles is caused by the same virus that causes chickenpox. Most people are exposed to this virus during childhood. After the primary infection (chickenpox), the virus becomes dormant, or inactivated. In some people, the infection reactivates years, or even decades later and causes shingles. Also known as herpes zoster.
SMALLPOX An acute, highly infectious, often fatal disease caused by a poxvirus and characterized by high fever and aches with subsequent widespread eruption of pimples that blister, produce pus, and form pockmarks. Also called variola.
TETANUS Causes painful muscle spasms in the neck, arms, legs, back, and abdomen. It can lead to "locking" of the jaw so the person cannot open his mouth or swallow. Tetanus can lead to death. (pink book chapter on tetanus) (view photo)
THIMEROSAL Thimerosal is a mercury-containing preservative that has been used in some vaccines and other products since the 1930's. There is no evidence that the low concentrations of thimerosal in vaccines have caused any harm other than minor reactions like redness or swelling at the injection site. However, in July 1999 the U.S. Public Health Service, the American Academy of Pediatrics, and vaccine manufacturers agreed that thimerosal should be reduced or eliminated from vaccines as a precautionary measure. Today, all routinely recommended childhood vaccines manufactured for the U.S. market contain either no thimerosal or only trace amounts.
VACCINATION Injection of a killed or weakened infectious organism in order to prevent the disease.
VACCINE Interacts with the immune system and often produces an immune response similar to that produced by the natural infection, but does not subject the recipient to the disease and its potential complications. Produces immunologic memory similar to that acquired by having the natural disease. There are two types: live attenuated and inactivated.
VACCINE ADVERSE EVENT REPORTING SYSTEM (VAERS) A database managed by the Centers for Disease Control and Prevention and the Food and Drug Administration. VAERS provides a mechanism for the collection and analysis of adverse events associated with vaccines currently licensed in the United States. Reports to VAERS can be made by the vaccine manufacturer, recipient, their parent/guardian or health care provider. For more information on VAERS call (800) 822-7967.
VARICELLA Also known as chickenpox. An itchy skin rash that can lead to scarring. It can also result in serious complications such as pneumonia, swelling of the brain, and possibly death. (pink book chapter on varicella) (view photo)
Public Health has made reasonable efforts to provide accurate translation. However, no computerized translation is perfect and is not intended to replace traditional translation methods. If questions arise concerning the accuracy of the information, please refer to the English edition of the website, which is the official version.
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