Immunization. Historical point

Transcription

1 Immunization Historical point In 1796 Edward Jenner s use of material from cowpox pustules to provide protection against smallpox. Louis Pasteur s 1885 rabies was the next to make an impact on human disease 1923 dyphtheria 1926 pertusis 1955 IPV 1960 OPV 1964 Measles Taking pus from a cowpox lesion on a milkmaid s hand, Jenner inoculated an eight-year-old boy, James Phipps. Six weeks later Jenner variolated two sites on Phipps s arm with smallpox, yet the boy was unaffected by this as well as subsequent exposures Active immunity Resistance developed in response to stimulus by an antigen (infecting agent or ) and is characterized by the production of antibodies by the host. Passive immunity Immunity conferred by an antibody produced in another host. It may be acquired naturally or artificially (through an antibody-containing preparation). 1 P a g e

2 Immunization: is the process by which an individual's immune system becomes fortified against an agent (known as the immunogen).through either active or passive immunization Vaccination: is a process of live attenuated, inactivated, fractionate of organism Immunizing agents include (s, immunoglobulin, and antisera) Immunoglobulins There are 5 major classes: IgM, IgA, IgG, IgE, IgD. Two types of immunoglobulin preparations are available for passive immunization: o Normal human immunoglobulin o Specific (hyper-immune) human immunoglobulin Antisera or antitoxins These are materials prepared in animals or non-human sources such as horses. Immunoglobulin and antiserum Human normal immunoglobulin Human specific immunoglobulin Non-human Ig (antisera) Hepatitis A Measles Rabies Tetanus Mumps Hepatitis B Varicella Diphtheria Diphtheria Tetanus Gas gangrene Botulism Rabies Vaccination Vaccination is a method of giving antigen to stimulate the immune response through active immunization. A is an immuno-biological substance designed to produce specific protection against a given disease. A is antigenic but not pathogenic. Types of s Live s Attenuated live s Inactivated (killed s) Toxoids Polysaccharide and polypeptide (cellular fraction) s Surface antigen (recombinant) s. Live s Live s are made from live infectious agents without any amendment. The only live is Variola small pox, made of live vaccinia cow-pox virus (not variola virus) which is not pathogenic but antigenic, giving cross immunity for variola. 2 P a g e

3 Live attenuated (avirulent) s Virulent pathogenic organisms are treated to become attenuated and avirulent but antigenic. They have lost their capacity to induce full-blown disease but retain their immunogenicity. Live attenuated s should not be administered to persons with suppressed immune response due to: o Leukemia and lymphoma o Other malignancies o Receiving corticosteroids and anti-metabolic agents o Radiation o Pregnancy Inactivated (killed) s Organisms are killed or inactivated by heat or chemicals but remain antigenic. They are usually safe but less effective than live attenuated s. The only absolute contraindication to their administration is a severe local or general reaction to a previous dose. Toxoids They are prepared by detoxifying the exotoxins of some bacteria rendering them antigenic but not pathogenic. Adjuvant (e.g. alum precipitation) is used to increase the potency of. The antibodies produces in the body as a consequence of toxoid administration neutralize the toxic moiety produced during infection rather than act upon the organism itself. In general toxoids are highly efficacious and safe immunizing agents. Polysaccharide and polypeptide (cellular fraction) s They are prepared from extracted cellular fractions e.g. meningococcal from the polysaccharide antigen of the cell wall, the pneumococcal from the polysaccharide contained in the capsule of the organism, and hepatitis B polypeptide. Their efficacy and safety appear to be high. Surface antigen (recombinant) s It is prepared by cloning HBsAg gene in yeast cells where it is expressed. HBsAg produced is then used for preparations. Their efficacy and safety also appear to be high. 3 P a g e

4 Types of s Live s *Small pox variola Live attenuated s *BCG *Typhoid oral *Plague *Oral polio *Yellow fever *Measles *Mumps *Rubella *Intranasal Influenza *Typhus Killed inactivated s *Typhoid *Cholera *Pertussis *Plague *Rabies *Salk polio *Intramuscular influenza *Japanese influenza Toxoids *Diphtheria *Tetanus Cellular fraction s *Meningococcal polysaccharide *Pneumococcal polysaccharide *Hepatits B polypeptide Recombinant s *Hepatitis B Routes of administration Deep subcutaneous or intramuscular route (most s) Oral route (sabine, oral BCG ) Intradermal route (BCG ) Scarification (small pox ) Intranasal route (live attenuated influenza ) Scheme of immunization Primary vaccination o One dose s (BCG, variola, measles, mumps, rubella, yellow fever) o Multiple dose s (polio, DPT, hepatitis B, hib) Booster vaccination o To maintain immunity level after it declines after some time has elapsed (DT, MMR,opv). Periods of maintained immunity due to s Short period (months): cholera vacc Three to five years: DPT Five or more years: BCG Ten years: yellow fever Solid immunity: measles, mumps, and rubella s. Levels of effectiveness Absolutely protective(100%): yellow fever Almost absolutely protective (99%): Variola, measles, mumps, rubella s, and diphtheria and tetanus toxoids. Highly protective (80-95%): polio, BCG, Hepatitis B, and pertussis s. Moderately protective (40-60%) cholera, and influenza killed. 4 P a g e

5 Storage Among the s, polio is the most sensitive to heat, requiring storage at minus 20 degree C. Vaccines which must be stored in the freezer compartment are: polio and measles. Vaccines which must be stored in the COLD PART but never allowed to freeze are : typhoid, DPT, tetanus toxoid, DT, BCG The Cold Chain The "cold chain" is a system of storage and transport of s at low temperature from the manufacturer to the actual vaccination site. The cold chain system is necessary because failure may occur due to failure to store and transport under strict temperature controls. Recommended Age Vaccines Birth BCG, Hepatitis B (HBV) OPV 0 2 Months [DTP, HIB] PENTA, OPV1, ROTA1 4 Months [DTP, HIB] TETRA, Oral Polio Vaccine (OPV2), ROTA2 6 Months [DTP, HIB, HBV] PENTA, OPV3, ROTA3 9 Months Measles Vaccine (mono) + Vit A Months MMR 1 st Booster Dose (OPV) 18 Months 1 st Booster Dose DTP, HIB Vit A nd Booster Dose (OPV) 4-6 Years 2 nd Booster Doe DTP MMR 2 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: 1. Reactions inherent to inoculation 2. Reactions due to faulty techniques 3. Reactions due to hypersensitivity 4. Neurological involvement 5. Provocative reactions 6. Others 1. Reactions inherent to inoculation: These may be local general reactions. The local reactions may be pain, swelling, redness, tenderness and development of a small nodule or sterile abscess at the site of injection. The general reactions may be fever, malaise, headache and other constitutional symptoms. Most killed bacterial s (e.g., typhoid) cause some local and general reactions. Diphtheria and tetanus toxoids and live polio cause little reaction. 5 P a g e

6 2. Reactions due to faulty techniques: Faulty techniques may relate to faulty production of (e.g. inadequate inactivation of the microbe, inadequate detoxication), too much given in one dose, improper immunization site or route,, stored incorrectly, contraindications ignored (e.g. a child who experienced a severe reaction after a previous dose of DPT is immunized with the same ), Use of improperly sterilized syringes and needles carry the hazard of hepatitis B virus, and staphylo - and streptococcal infection 4. Neurological involvement: Neuritic manifestations may be seen after the administration of serum or. The well-known examples are the post-vaccinial encephalitis and encephalopathy following administration of anti -rabies and smallpox s. Guillain-Barre syndrome in association with the swine influenza is another example. 5. Provocative reactions: Occasionally following immunization there may occur a disease totally unconnected with the immunizing agent (e.g., provocative polio after DPT or DT administration against diphtheria). The mechanism seems to be that the individual is harboring the infectious agent and the administration of the shortens the incubation period and produces the disease or what may have been otherwise only a latent infection is converted into a clinical attack. 6. Others: These may comprise damage to the fetus (e.g., with rubella vaccination); displacement in the age-distribution of a disease (e.g., a potential problem in mass vaccination against measles, rubella and mumps). Application of active immunization Infants and children expanded immunization program (schedule) Active immunization for adult females Vaccination for special occupations Vaccination for special life styles Vaccination for special environmental situations Vaccinations for special health status persons Vaccinations in travel 6 P a g e

7 Compulsory (obligatory) vaccination for infants & booster vaccination for children (Expanded immunization program) See local schedule of vaccination Note (children failing to complete childhood vaccination schedule) Vaccination for special occupations Health care workers: hepatitis B, influenza, MMR, polio Public safety personnel (police, fire fighters) and staff of institutions for the developmentally disabled: hepatitis B, influenza Vets and animal handlers: rabies, plague and anthrax Sewage workers: DT, hepatitis A, polio, TAB Food handlers: TAB Military troops and camp dwellers: pneumococcal, meningococcal, influenza, BCG (for non reactors), tetanus Vaccinations for special health status persons Immuno-compromised persons (Leukemia, lymphoma, HIV, malignancy ) Hemodialysis and transplantation should receive the following s according to their situation: o HBV, Influenza, Pneuomococcal s General Contraindications Moderate or severe illness with or without fever Anaphylactic reaction to or constituent Live attenuated s o Pregnant women o Immunocompromised / Immunosuppressed children o Within 3-11 months of immunoglobulin administration Invalid Contraindications Mild to moderate local reaction Mild acute illness with or without low grade fever Current antimicrobial therapy Convalescent phase of illnesses Prematurity and low birth weight History of penicillin or other nonspecific allergies Malnutrition Immunization of Special Groups IMMUNOCOMPROMISED HOSTS Avoid MMR, measles (may be used in HIV) Avoid OPV; use IPV for these children and their household contacts PRETERM INFANTS Treat as term babies Avoid OPV in hospital Influenza in BPD May delay HBV if <2 kg & mother is HBsAG negative 7 P a g e