Immunity & immunization Prepared by :Entisar Nasrallah Pediatric Department
The different types of vaccines used Vaccine Safety Lecture outline Principles of Vaccination Vaccine Storage and Handling Item 1 Item 2 Item 3 Item 4 Item 5 Vaccine Administration Vaccine Adverse Reaction Item 6
History of vaccination • Historical recordings of attempts of vaccination from 7th century but not really recognised or successful until: • 1796: Edward Jenner demonstrated that inoculation with cowpox virus produced protection from infection with smallpox. • (Hence “Vaccination”: taken from vacca – the Latin word for cow) • 1860s-1890s: Louis Pasteur produced vaccines against chickenpox, cholera, diphtheria, anthrax and rabies
History of vaccination • Early 20th Century: Toxoid vaccines against diphtheria and tetanus produced following discovery of effective inactivation with chemicals • Post World War 2: successful live viral vaccines developed using cell culture techniques • Present and future: new technologies constantly developing: recombinant protein vaccines, DNA and conjugate vaccines
Principles of Vaccination Passive immunity is protection by products by an animal or human and transferred to another human, usually by injection This protection wanes with time, usually within a few weeks or months Active immunity is protection by the person's own immune system This type of immunity usually permanent Immunity: is the ability of the human body to tolerate the presence of material indigenous to the body “self”, and to eliminate foreign “non self” material. • Immunity to a microbe is usually indicate by the presence of antibody to that organism • Immunity is generally specific to a single organism or group of closely related organisms. • There are tow basic mechanism for acquiring immunity :
Immunity Specific defenses Immunity Active immunity Passive immunity Following clinical infection natural Transfer of maternal Antibodies Through placenta Transfer of maternal Antibodies Through milk Following sub clinical infection acquired Following administration of Immunoglobulin or antiserum Following vaccination
Immunizing agents Immunizing agents vaccines immunoglobulin antisera
Vaccination Vaccination is a method of giving antigen to stimulate the immune response through active immunization. A vaccine is an immuno-biological substance designed to produce specific protection against a given disease. A vaccine is “antigenic” but not “pathogenic”.
The importance of vaccine safety programs • Decrease in disease risks • Public confidence
Immunization can save money • Immunization is one of the most cost-effective health interventions. • Investing in vaccines SAVES more money than it costs.
Types of vaccines Live attenuated vaccines These vaccines contain a version of living virus that has been weakened so that it does not cause serious disease in people with healthy immune system (e.g. MMR) Toxoid vaccines Prevent diseases caused by bacteria that produce toxin in the body . The toxins are weakened so they cannot cause illness. Weakened toxin called toxoids. Inactivated vaccines These vaccines are made by inactivating or killing , the virus during the process of making the vaccine ( e.g, polio vaccine)
Diseases Caused by Bacteria • Diphtheria • Haemophilus influenzae type b • Meningococcal disease • Pertussis • Pneumoccocal disease • Tetanus
This child has diphtheria and has developed a pseudo-membrane, a thick gray coating over the back of his throat. Photo courtesy of CDC Diphtheria
This child has a swollen face due to Hib infection. Haemophilus influenzae type b
This 4-month-old has gangrene due to infection with meningococcus. Photo courtesy of CDC Meningococcal Disease
Child with broken blood vessels in eyes and bruising on face due to severe coughing caused by pertussis. Pertussis
This child was experiencing painful muscle spasms due to infection with tetanus. Courtesy CDC Tetanus
Diseases Caused by Viruses • Hepatitis A • Hepatitis B • Shingles • Human papillomavirus (HPV) • Influenza • Measles • Mumps • Rotavirus • Chickenpox • Polio
This man developed jaundice as a result of hepatitis A infection.Courtesy CDC Hepatitis
This photo shows how influenza germs spread through the air when someone coughs. Courtesy CDC Influenza
This child is very swollen under the jaw and in the cheeks due to mumps. Courtesy CDC Mumps
This child was born with cataracts caused by a rubella infection his mother transmitted to him before birth. Courtesy CDC Rubella
Routes of administration Deep subcutaneous or intramuscular route (most vaccines) Oral route (Sabine vaccine) Intradermal route (BCG vaccine) Scarification (small pox vaccine) Intranasal route (live attenuated influenza vaccine)
Factors may influence the immune response to vaccination • The presence of maternal antibodies • Nature and dose of antigen • Route of administration &presence of an adjuvant (improve the immunogenicity of the vaccine) • Host factors such as (age, nutritional status, and coexisting disease)
Scheme of immunization Primary vaccination One dose vaccines (BCG, variola, measles, mumps, rubella, yellow fever) Multiple dose vaccines (polio, DPT, hepatitis B) Booster vaccination To maintain immunity level after it declines after some time has elapsed (DT, MMR).
Periods of maintained immunity due to vaccines Short period (months): cholera vaccine Two years: TAB vaccine Three to five years: DPT vaccine Five or more years: BCG vaccine Ten years: yellow fever vaccine Solid immunity: measles, mumps, and rubella vaccines.
Levels of effectiveness Absolutely protective(100%): yellow fever vaccine Almost absolutely protective (99%): Variola, measles, mumps, rubella vaccines, and diphtheria and tetanus toxoids. Highly protective (80-95%): polio, BCG, Hepatitis B, and pertussis vaccines. Moderately protective (40-60%) cholera vaccine, and influenza killed vaccine.
HAZARDS OF IMMUNIZATION No immune response is entirely free from the risk of adverse reactions or remote squeal. The adverse reactions that may occur may be grouped under the following heads: Reactions inherent to inoculation Reactions due to faulty techniques Reactions due to hypersensitivity Neurological involvement Provocative reactions Others
Contraindication :is a condition that greatly increases the chance of a serious adverse reaction.(MMR) • Precaution:a condition that might increase the chance or severity of a serious adverse reaction.
General Contraindications • Permanent Contraindications: All vaccines • Anaphylactic reaction to prior dose of vaccine • Anaphylactic reaction to a component of the vaccine
Conditions are considered permanent • Severe (anaphylactic) allergic reaction to a vaccine component or following a prior dose. • Encephalopathy not due to another identifiable cause occurring 7 days of pertussis vaccine • Severe combined immunodeficiency • A history of intussusceptions after rotavirus vaccine • Temperature of 40.0C within 48 hours of a dose (DTP) • Shock like status, persistent crying, seizure. (3 days )
General Contraindications/ Precautions • Temporary Contraindications or Precautions • Moderate-to-severe illness (all vaccines) • Pregnancy /possibility of pregnancy in next 4 weeks • Immunosuppression • Administration of blood products within the last year • Long term steroid use • Note: additional contraindications and precautions apply to specific vaccines
Screening for contraindications and precautions to vaccination • Is the child sick today? • Does the child have allergies medications, food, or any vaccine? • Has the child had a serious reaction to a vaccine in the past? • Has the child had a seizure, or brain or nerve problem? • Has the child a health problem with asthma, lung disease, kidney disease, metabolic disease such as diabetes, or a blood disorder?
Does the child have cancer, leukemia, ADIS, or any other immune system problem? • Has the child taken cortisone, prednisone, other steroids, or anticancer drugs, or had x-ray treatments in the past 3 months? • Has the child received a transfusion of blood or blood products, or been given a medicine called immune (gamma) globulins in the past year? • Is the child/pregnant pregnant or there is a chance she could become pregnant during the next month? • Has the child received vaccination in the past 4 weeks?
Diluents are NOT Interchangeable Wrong diluent is inadvertently used, the immunization may need to be repeated. The diluent for MMR, MMRV, Varicella, and Zoster are the same
Administrative Error: Combining Vaccines into one Syringe that Shouldn’t be Together Two different vaccines should NEVER be combined in the same syringe unless FDA licensed for use in this way +
Risk of reactions versus risk of disease • For all vaccine-preventable diseases, the risk of complications is much greater than risk of a serious adverse reaction following vaccinatione.g. Natural measles, mumps or rubella infection versus MMR vaccine
Timing of Vaccine Reactions • Inactivated vaccines: generally within 48hrs following vaccination • Live vaccines: occur according to time taken for virus to replicate • e.g. MMR vaccine: • reactions to measles component (malaise, fever, rash) tend to occur 6 to 11 days following vaccination • reactions to rubella component (pain, stiffness or swelling of joints) tend to occur in 2nd week following vaccination • reactions to mumps component (parotid swelling) tend to occur in 3rd week following vaccination (although may occur up to 6 weeks following vaccination)
Adverse events • Live vaccines: frequency of adverse events falls with number of doses • Eg MMR • Because if antibody is made in response to first dose of live vaccine, it neutralises the small amount of vaccine virus in any subsequent vaccine dose • Inactivated vaccines: frequency of adverse events increases with number of doses • Eg tetanus, pertussis • Because if antibody levels are good following previous vaccination, the antibody binds to the vaccine antigen in a subsequent dose of vaccine making an inflammatory response (such as a sore arm).
Interval Spacing of vaccines • Doses of the same inactivated vaccine – 4 weeks apart (or 8w for PCV) • Live vaccines (same or different) – 4 weeks apart • No interval need be observed between: • live and inactivated vaccines • doses of different inactivated vaccines • No evidence exists that inactivated vaccines interfere with the immune response to other inactivated vaccines or to live vaccines. An inactivated vaccine can be administered either simultaneously or at any time before or after a different inactivated vaccine or live vaccine