חיסונים בגיל הילדות

1. חיסונים בגיל הילדות פרופסור יהודה דנון מרכז שניידר לרפואת ילדים ydanon@post.tau.ac.il הרצאה בי"ס לרפואה מאי 2007

2. Aims & objectives of immunization • prevention of serious diseases and their complications • protection of individuals and communities • containment of outbreaks • elimination of certain diseases, e.g. tetanus • eradication of diseases, e.g. smallpox (1980) & polio (target date 2005)

3. World situation • World Health Organization (WHO) - Expanded Programme on Immunization (EPI) 1974 • six target diseases: diphtheria, tetanus, pertussis, polio, measles & tuberculosis • inequity to vaccination programmes: R&D & funding of new & existing vaccinesimmunisation safetyState of the World’s Vaccines and Immunization, WHO, 2002

4. Decisions to introduce a vaccine • is the disease important enough? • can a safe and effective vaccine be produced? • is it acceptable to recipients, their parents or carers? • is it cost effective? • can enough people in the target group be immunised to make the programme effective?

5. Different types of vaccines • Inactivated vaccines:killed whole organisms e.g. pertussisinactivated bacterial toxins, e.g. diphtheria & tetanusacellular vaccine e.g. pertussis • Polysaccharide vaccinesplain polysaccharide e.g. pneumococcal for over 2spolysaccharide conjugate e.g. Hib, MenC • Live attenuated e.g. MMR, polio & BCG • Combination vaccines e.g. DTP-Hib, MMR

6. Development of safe, effective vaccines • Pre-clinical trials • volunteers and protocols • clinical trialsPhase I studiesPhase II studiesPhase III studies • licensure • immunisation policy

7. Monitoring vaccine safety • routine testing before release • Phase lV studies - Post-Licensing Evaluation • “Yellow card” system • studies of vaccine safety cohort studies case-control studies record linkage

8. Contraindications & precautions • Contraindications: severe local or systemic reactions to preceding doseslive vaccines because of disease temporary contraindications: live vaccines in the immunosuppressed due to treatment - chemotherapy, radiotherapy, high dose corticosteroids, organ transplantation with concurrent & immunosuppressive treatment • Precautions:increased risk of reaction or compromised immunity

9. Adverse events • all medicines, including vaccines can cause adverse events • three general categories:localsystemicallergic • real v myth

10. Benefits and risks • the benefit of the vaccination outweighs the risk of the disease and associated morbidity and mortality • the risk of adverse events to an immunization outweighs the risk of the disease and associated morbidity and mortality

11. Successful immunisation • production of a safe and effective vaccine • maintaining cold chain from point of manufacture to administration • ordering and storage • consent • injection into correct site using the correct technique • Immune response in individual

12. Public & professional knowledge • Bi-annual tracking of mothers:knowledge about immunisationattitudes towards immunisationexperience of immunisation servicesresponse to advertising using key indicators • annual health professional survey:impact of publicityawareness & evaluation of materialsassessing the needs of GPs, practice nurses & health visitors

13. Information • Resources:leaflets, factsheets, FAQs, websites, green book, posters, videosprofessional mailings - CMO letters/updates • Advertising: TV & radio, parent and professional journals, newspapers • press & public relations

14. Professional responsibility • responsibility of being reliably informed • responsibility of not just simply providing the facts, but of our own informed opinion and support for immunisation • responsibility for promoting immunisation as the most important of all medical interventions

15. It is every child’s right to be protected against infectious disease. No child should be denied immunisation without serious thought as to the consequences, both for the individual child and for the community

17. Factors influencing the immune response to vaccination • Presence or absence of maternal antibodies • Nature and dose of antigen administrated • Mode of administration of vaccine • Adjuvant

19. Dynamics of antibody formation • Primary immune response • Latency period • Growth period • Period of decline • Secondary response

20. Viral vaccines • Live attenuated vaccines: Oral poliomyelitis (OPV), Measles, Mumps, Rubella, Yellow fever • Inactivated vaccines: Influenza, Rabies, Injectable poliomyelitis (IPV)

21. Bacterial vaccines • Live attenuated: BCG • Killed vaccine: pertussis, typhoid, cholera • Toxoid: Diphteria, Tetanus • Polysaccharide vaccines: Meningococcal Atc. Pneumococcal

22. Vaccines produced on embryonic eggs or chick embryo • Influenza vaccine • Yellow fever vaccine • Measles vaccine • Mumps vaccine

29. Diphtheria Immunization • The immunizing antigen is toxoid prepared by corynebacterium diphteriae toxin • Provided in combination with Tetanus • DT • Td • DTaP • DTP • Aluminium hydroxide as adjuvant

33. Tetanus Immunization • Neurotoxicity by a potent exotoxin of Clostridium tetanii (spore) • Common circumstances: • Contamination of the umbilicus of neonate • Wounds that result with pockets of anaerobiosis • Insect bites • Contamination of surgical wounds

35. Immunizing Agent-Tetanospamin • The toxin of C. Tetanii is modified by chemical treatment to provide a stable non toxic toxoid • T • DT • Td • DTaP

38. Pertussis Immunization • Classical pertussis vaccine; killed whole Bordetela pertussis inducing fragments of the organism • New pertussis vaccines composed of purified components of B. pertussis prepared from inactivated organisms acellular pertussis vaccine (aP) • aP • TaP • TDap

41. Poliomyelitis Immunization Inactivated poliovirus vaccines; A polyvalent vaccine containing formalin inactivated poliovirus types 1,2 and 3 grown on monkey kidney tissue culture (Salk, 1955) – IPV Since 1988 production in human diploid cells

43. Attenuated oral poliovirus vaccine Trivalent OPV (TOPV) is a mixture of polioviruses types 1,2, and3 grown on monkey kidney cells in t.c. or human diploid cell in t.c. (Sabin, 1961)

48. Measles in Israel

50. Measles (Rubeola) Immunization • Killed measles vaccine (KMV) (Fulginiti, 1963) • Live measles virus vaccine • Edmonston strain (1963) • Schwartz strain (1964) • Passages of LMV in chick embryo tissue culture • LMV • MMR • MM • MR