Immunization

1. Immunization

2. Immunization: • Immunization is the process of inducing immunity artificially by either vaccination (active imm.)or administration of antibodies (passive imm.)

3. Active immunization • Active immunization entails the introduction of a foreign molecule into the body, which causes the body itself to generate immunity against the target. This immunity comes from the T cells and the B cells with their antibodies

4. Passive immunization • This method of immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and if there are no B cells to produce more antibodies, they will disappear. • The antibodies can be produced in animals ("serum therapy") although there is a high chance of anaphylactic shock because of immunity against animal serum itself. Thus, humanized antibodies produced in vitro by cell culture are used instead if available. this basically means 87 different are being affected

5. important of immunization • eradication of disease EX: smallpox • Elimination of disease EX: polio • Control of disease EX: diphtheria

6. Immunizing agent: • Vaccine :a protein, polysaccharide or nucleic acid delivered to body to produce immunity • Toxoid:a modified bacterial toxin (not toxic but capable of producing antitoxin) • Antitoxin: antibodies derived from human or animal serum after stimulation with specific antigen

7. Constituents of vaccine : • Protein , polysaccharide ,nucleic acid • Preservative/stabilizer/antibiotics • Adjuvant (salts) • Suspending fluid • Component of organism: like influenza vaccine

8. Types of vaccines: • Live attenuated: • Prepared from attenuated strains that render them non-pathogenic . • Usually effective with one dose as they replicate in the host and provide antigenic stimulation for long time.

9. Types of vaccines: • Reversion to original pathogenic form causing full-blown is rare but possible especially in immunocompromised individuals,so we prefer to avoid live vaccine in most immunocompromised patients. • EX: BCG, MMR, OPV, Varicella, Measles.

10. Inactivated or killed : 1. Inactivated whole organism : Hepatitis A, whole cell pertusses 2. Detoxified exotoxins : Tetanus , Diphtheria 3. Purified protein antigen: Acelluarpertusses , Hepatitis B 4. Polysaccharide: Capsular Meningococcal 5. Capsular polysaccharide conjugated to protien: Hib, Pnemoccocal conjugated vaccine 6. Component of organism: Influenza vaccine Generally require3-5 doses to be effective

11. Immune response to vaccine: • In live attenuated vaccines ,the organisms multiply in recipient so it is more like the natural infection ,so it is likely to produce life long protection after 1st dose of vaccine. • Killed vaccines :less antigenic so usually need booster doses.

12. Nature and magnitude of immune response depend on many factors: 1. Age at administration 2. Presence of maternal antibodies younger than 6 months 3. Relative immaturity of immune system 4. Host factors: nutrition, immunity 5. Route of administration: IPV ,OPV Subcutaneous hepatitis B at buttock less immunogenic than IM at deltoid

13. T cell independent antigens are those that produce B cells proliferation and antibody production without help of T cells • T cell independent antigens are poor immunogenic in younger than 2 years • So conjugation with protein carrier will induce more immunity like Hib ,Conjugated pneumoccocal vaccine. • Primary response to a vaccine : IGM serum antibody is usually detected 7-10 days then IGG type peaks at 2-6 weeks.

14. Vaccine schedules: • Generally a vaccine is recommended at the youngest age at which significant risk of a disease and complication exist and at which protective immune response is expected. • Either universal schedules or for selected populations e.g. : specific diseases (nephrotic syndrome…) travel (yellow fever vaccine…) post exposure (rabies…)

15. Special conditions: • Most vaccines can be given simultaneously without impairment of vaccines effectiveness or safety • Breast feeding is not a contraindication to any vaccine ,although most live attenuated vaccines replicate in mother they are not excreted in human milk.

16. Special conditions: • Lapsed immunizations: If interval between vaccine doses exceed those recommended ,this does not adversely affect the immune response provided the series is completed, so no need to restart the series or to give extra doses.

17. Preterm infants: • Immune response to vaccination is a function of postnatal age rather than gestational age • Prematurity does not increase the incidence of vaccine related adverse effects • Doses are same as those for term infants (NOT reduced) • Should be vaccinated at same chronological age as full term ,according to schedule .

18. Corticosteroids: • Physiologic or low doses (less than 2mg/kg/day) of prednisone ,inhaled or topical steroids the child can be immunized while on steroid. • More than 2mg/kg/day,or alternate-day steroid for less than 14 days ,should have live vaccine deferred until at least stoping steroid. If more than 14 days defer the vaccine for at least 1 month.

19. Immunodeficiency: • Depends on degree of immunodeficiency and underlying cause. • Generally ,live attenuated vaccines are contraindicated e.g. OPV • Some other vaccines are indicated e.g. Influenza vaccine and Pneumoccocal vaccine

20. General notes: • Contraindications: Severe allergic reactions after a vaccine dose or to some vaccine component • Precautions: Moderate or severe acute illness with or with out fever (benefits & risks of a vaccine is individualized) • Adverse effects: Usually Mild Problems : Redness, warmth, swelling ,Fever

21. BCG

22. BCG: • There is evidence that BCG provides appreciable protection against tuberculosis meningitis (50-80%) and miliary disease. • Intra-dermal injection

23. BCG: • Local lesion, papule, 2 weeks after vaccination. • Small abscess might develop, 4-6 weeks. • At 6 weeks (crust, detaches, ulcerates) ,then a scar (typically round and slightly depressed) remains

24. BCG: • Complications: 1. Local abscess 2. “Not so serious” Lymphadenitis Non-suppurative ,Suppurative 3. Serious Lymphadenitis : Persistent, recurrent or multiple 4. BCG osteitis 5. Disseminated BCGosis in immune compromised

25. BCG: • Contraindications: only “symptomatic HIV infection (i.e. AIDS)” is a contraindication for BCG according to WHO. 8

26. DTP Vaccine

27. DTP Vaccine: • Inactivated whole organism vaccine DTP or Acellular vaccine DTaP • Acellular type has less side effects • After 6 years of age only Td is given 9

28. DTP Vaccine: Side effects : • Mild Problems (Common): Fever, Redness, swelling, Soreness (1 in 4) Fussiness ,Tiredness or poor appetite and Vomiting (1 in 50) These problems occur more often after the 4th and 5th doses of the DTP series than after earlier doses.

29. DTP Vaccine: • Moderate Problems (Uncommon): Seizure (1 in 14,000), Non-stop crying for 3 hours or more (1 in 1,000), High fever (1in 16,000) • Severe Problems (Very Rare) : Serious allergic reaction (1 in a million dose) Long-term seizures, coma, or lowered consciousness , Permanent brain damage. so RARE that it is hard to tell if they are caused by the vaccine.

30. DTP Vaccine: • Contraindications: 1. Encephalopathy (coma ,altered level of consciousness ,prolonged seizures ) within 7 days of previous dose 2. Progressive neurological disorder till neurological state is clarified.

31. Precautions: 1.Fever more than 40.5,during 48 hrs of previous dose 2. Collapsed or shock like state during 48 hrs of previous vaccine dose 3. Seizures during 3 days or less of previous vaccine dose 4. Persistent inconsolable crying more than 3 hr during 48 hr of previous vaccine dose

32. Hepatitis B vaccine

33. Hepatitis B vaccine: • Is a very safe vaccine • Very effective • Infants born to HBsAg-positive mothers should receive the vaccine and HBIG within 12hr of birth.

34. Hib Vaccine

35. Hib Vaccine: • Capsular polysaccharide conjugated to protein carrier • Contraindicated in less than 6 weeks of age • Children over 5 years old usually do not need Hib vaccine Need, don’t? 10

36. OPV, IPV

37. OPV, IPV: • live attenuated oral polio vaccine (OPV) • IPV is inactivated vaccine • IPV elicit higher serum IgG antibody levels but OPV also produce mucosal IgA immunity and limit virus replication in gastrointestinal system 11 Type of vaccine

38. OPV, IPV: • Side effects : IPV has no adverse effects OPV may cause (vaccine associated paralytic polio) in 1 in 6.2 million doses. 12

39. MMR vaccine

40. MMR vaccine: • Live attenuated vaccine • Subcutaneous injection • Side effects : Mild Problems : 1. Mild rash (1 in 20) 2. Swelling of glands in the cheeks or neck (rare) If these problems occur, it is usually within 7-12 days after the shot. They occur less often after the second dose

41. MMR vaccine: • Moderate Problems : 1. Seizure caused by fever (1 in 3,000 doses) 2. Temporary pain and stiffness in the joints, mostly in teenage or adult women (up to 1 out of 4) 3.Temporary low platelet count (1 in 30,000 doses)

42. MMR vaccine: • Severe Problems (Very Rare) : Serious allergic reaction (1 in a million doses) “Several other severe problems have been known to occur after a child gets MMR vaccine. But this happens so rarely, experts cannot be sure whether they are caused by the vaccine or not”

43. Contraindications: 1. A life-threatening allergic reaction to gelatin, neomycin, or to a previous dose of MMR vaccine 2. Pregnant women 3. known severe immunodeficiency like severely symptomatic HIV infection • Precautions: Recent blood transfusion or were given other blood products less than 11 months

44. Other Vaccines

45. Pneumococcal polysaccharide vaccine • 23 valent vaccine • Usually 2 doses • Help prevent serious pneumococcal disease e.g.meningitis, bacteremia, pneumonia • Anyone older than 2 years with: heart disease, lung disease, sickle cell disease, diabetes, cirrhosis ,lymphoma, leukemia , kidney failure ,nephrotic syndrome , asplenia, HIV infection or AIDS • Minor side effects

46. Pneumococcal Conjugate Vaccine • 7 valent vaccine • Help prevent serious pneumococcal disease e.g.meningitis, bacteremia, pneumonia • Also prevent some otitis media • Children under 2 years of age: 2 months - 4 months - 6 months – 12 to 15 months • Minor side effects

47. Varicella vaccine: • Can prevent chickenpox and if got chickenpox it is mild, fewer spots, less likely to have a fever, and will recover faster • First dose: 12- 15 months of age Second dose: 4- 6 years of age (may be given earlier if at least 3 months after the first dose) • Minor side effects, moderate: (Seizure 1 in 1000),severe :Pneumonia (very rare)

48. Varicella vaccine: • Contraindications: 1. A life-threatening allergic reaction to gelatin, neomycin, or to a previous dose of Varicella vaccine 2. Pregnant women 3. known severe immunodeficiency • Precautions: Recent blood transfusion or were given other blood products less than 11 months

49. Influenza Vaccine : • Inactivated vaccine. • Influenza viruses are always changing ,so influenza vaccines are updated every year, and an annual vaccination is recommended in October or November . • It is recommended for anyone who is at risk of complications from influenza AND older than 6 months of age

50. Influenza Vaccine : • Minor side effects • Contraindications: Influenza vaccine virus is grown in eggs. People with a severe egg allergy should not get the vaccine