Immunity and Vaccinations Health Science

Objectives / Rationale The ability to develop immunity to diseases is a key factor in maintaining health and wellness. The student will learn the difference in naturally acquired and artificially acquired immunity and understand the importance of vaccinations for individual and community health.

The Immune System is the body’s special defense response against foreign organisms.

Immune system includes: Lymphoid organs –lymph nodes –spleen –thymus gland

Their products – –lymphocytes –antibodies Macrophages – phagocytes that are found in the blood, brain, liver, lymph nodes and spleen

*Immunity *The capacity to resist certain types of organisms and toxins (poisons) that will damage tissues and organs. *Natural (innate) Immunity – one’s own ability to fight off disease. By genetic predisposition, phagocytosis, macrophages.

*Acquired Immunity – the body develops specific immunity (antibodies and cells) against invading agents such as lethal bacteria, viruses, toxins, and even foreign tissues from other organisms.

*Acquired active immunity occurs in two ways: By having a disease Receiving a vaccination containing a modified pathogen or toxin, which stimulates production of antibodies.

Acquired passive immunity – the patient receives immune serum containing antibodies produced in another animal. Examples: antitoxins, gamma globulin

White Blood Cells Protect us from infection, and help us fight infection Neutrophils One of the body’s main defenses against bacteria. Kill bacteria by actually ingesting them (phagocytosis).

Eosinophils – kill parasites and have a role in allergic reactions Basophils – function in allergic reactions. They release: histamine – causes blood vessels to leak and attract WBCs, and

heparin – prevents clotting in the infected area so that the WBCs can reach the bacteria.

Lymphocytes – complex cells that direct the body’s immune system. T lymphocytes – (T cells) – they mature in the thymus and are responsible for cell-mediated immunity Four types of T Lymphocytes:

Helper T cells – direct the rest of the immune system by releasing cytokines which produce signals that regulate cell growth and function during the inflammatory response. Cytotoxic T cells – release chemicals that break open and kill invaders.

Memory T cells – remain afterwards to help the immune system respond more quickly if the same organism is encountered again. Suppressor T cells – suppress immune response so that it does not destroy normal cells

B Lymphocytes – responsible for humoral immunity (antibody production)

Monocytes – called ‘wandering’ cells until they enter a tissue where they become fixed and turn into macrophages. They destroy old, damaged and dead cells in the body.

Macrophages are found in the liver, spleen, lungs, lymph nodes, skin and intestine.

Naturally Acquired Immunity Active Immunity – immunity may be acquired by exposure to a disease. *Antigen – a substance that triggers an antibody response. An antigen can be anything from bacteria to pollen; dust to drug; food to animal.

People are born with certain antigens, such as those on the RBCs, depending on their blood type. An antigen doesn’t produce an allergic reaction in all people. Because…….

In hypersensitive people, the presence of an antigen combined with an antibody provokes the release of histamine which forms the basis for all allergic symptoms.

*Passive Immunity – immunity may be acquired naturally by a fetus through the passage of antibodies from the mother through the placenta or through breast milk to a nursing infant.

In this type of passive immunity, antibodies come from an outside source. These antibodies are temporary. They will protect for up to 6 months or longer if the mother continues nursing.

Artificially Acquired Immunity *Vaccination or immunization – an agent is introduced into the body to stimulate antibody production.

Vaccine is given by injection or liquid by mouth. Needle free: inhalation of aerosol or powder. The body makes antibodies against the weakened or killed pathogens from the vaccine.

These antibodies can fight the pathogens when they invade the body. The antibodies destroy them and the person will not become ill. Protective antibodies then stay on guard in the body to safeguard it from the real disease if the person ever becomes exposed to the real disease. This protection is immunity.

Vaccines Live organisms – must be nonvirulent for humans or treated in the lab to weaken them so that are not as pathogenic to humans. Attenuated – an organism that has been weakened.

Killed – vaccination with a toxoid occurs when the toxin produced by an organism is altered with heat or chemicals to render it harmless, but still allows the body to make antibodies against it.

*Examples of Vaccines *Anthrax – a serious disease that can affect both animals and humans. Contracted from infected animals, wool, meat, or hides Causes skin ulcers, fever, fatigue. 20% of the cases are fatal Inhaled anthrax is more serious.

Anthrax vaccine protects against both types of anthrax. Who should be vaccinated? Those y/o potentially exposed to large amounts of the virus – lab workers, military personnel at risk. Three doses given at 2 week intervals. Three additional doses each six months after the previous dose. Boosters.

*DPT – Diptheria, Tetanus, Pertussis Diptheria – causes a thick covering on the back of throat, can lead to breathing problems, paralysis, heart failure and death. Tetanus – causes painful tightening of muscles, leading to “lockjaw” – cannot open mouth or swallow; leads to death in 1 out of 10 cases.

*Pertussis (whooping cough) – causes coughing spells so bad it is hard to eat, drink, breathe. Can lead to pneumonia, seizures, brain damage, death. Children should receive 5 doses of the DtaP vaccine. Mild risks and serious risks involved.

*Hemophilus Influenza, Type b (Hib) Serious disease caused by a bacteria. Hib is spread person-to-person. If it remains in nose and throat, the person will not get sick. If it moves to the lungs or blood stream, can be serious.

*Hepatitis A Vaccine – Hepatitis A is a serious liver disease caused by Hep A virus, found in stool of persons with Hep A. Can be spread by close personal contact or by eating food or drinking water contaminated by it. Causes mild flu-like illness, jaundice, stomach pain, diarrhea.

Hep A vaccine should be given in 2 doses at least 2 months apart. Who should get? Travelers to or residents of countries with high rates of Hep A – 1 month before traveling; homosexual men; street drug users; individuals with chronic liver disease.

*Hepatitis B Vaccine – Hep B (HBV) is serious. Can cause acute or chronic illness million people in U.S. have chronic HBV. Each year, it is estimated that 80,000 people, mostly young adults will get it; people will die each year.

HBV is spread through contact with blood and body fluids of an infected person: having unprotected sex, sharing needles, being stuck with an infected needle, during birth when passed from mother to baby. Who should get? those 18 y/o and younger. High risk adults. Three doses

*Influenza Vaccine – Influenza is caused by a virus; spreads form infected persons to nose or throat of others. Usually Nov through April. Causes fever, cough, chills, sore throat, headache, muscle aches. Causes thousands of deaths annually. The virus changes often. Let’s look at a Brainpop video on flu.

*Lyme Disease Vaccine – Lyme disease is caused from being bitten by an infected tick. Common sign is a round, red, expanding rash 2 inches or more in diameter btw 3 days and a month after the tick bite. Fever, chills, headaches, joint and muscle pain can also occur. Can lead to arthritis, heart rhythm prob

*Measles, Mumps, Rubella (MMR) – Measles virus causes rash, cough, runny nose, eye irritation, fever. Mumps causes fever, headache & swollen glands and can lead to deafness, meningitis, painful swelling of testicles or ovaries, death. Rubella (German Measles) causes rash, mild fever, arthritis.

If a woman gets rubella while pregnant, she could miscarry, or her baby could be born with serious birth defects. Who should get the MMR vaccine? Children (2 doses) Adults born after 1956

*Meningococcal vaccine – meningococcal disease is a serious illness caused by a bacteria; is the leading cause of bacterial meningitis. Is an infection of the brain and spinal cord covering. Who should get? U.S. Military recruits

People exposed during an outbreak Travelers to a country where it is common Anyone who has a damaged or removed spleen Lab workers routinely exposed to the bacteria College students living in a dorm

*Polio vaccine – polio is a disease caused by a virus that enters through the mouth and can cause paralysis and death. No “wild” polio has been reported in the U.S. for > 20 years. Still common in some parts of the world.

*Smallpox – last natural case of smallpox occurred in 1977, and in 1980, the World Health Organization (WHO) declared the global eradication of smallpox and recommended that all countries cease vaccination. Because of concerns that the virus could be used as a bioterrorism weapon, the CDC has a plan.

The plan will coordinate CDC, state, and local public health activities if an outbreak occurs, and it will help health officials define and control the outbreak. This includes indications for vaccination, contraindications for vaccination, risks, sites, personnel, facilities, etc.

*Tetanus and Diptheria Vaccine – (Td) – Tetanus is caused by a germ that enters the body through a cut or wound. Diptheria spreads from person to person. People get the original vaccination after 7 y/o. Should also get one every 10 years throughout their life.

*Varicella (chickenpox) vaccine – the virus can spread from person to person through the air, or by contact with fluid from the blisters. A person who has had chickenpox can get a painful rash – herpes zoster (shingles) – later in life.

With any vaccine, there are risks and contraindications. Each person should be evaluated as to which vaccines they should or should not receive. Immunity may not be life-long with vaccines. Sometimes, booster shots are needed to keep antibody levels high enough for protection.