Immunisation

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If you understand basic immunology you can explain... How vaccines work and why vaccine failures occur Adverse events and their timing Why the schedule is as it is Why vaccines cannot overload the immune system

Physical barriers Skin – 2 m² Mucosal membranes – digestive, respiratory, reproductive tract – 400 m²

Innate immunity Phagocytosis Macrophage - WBC Rapid action 0-4 hours Non-specific – same response each time No memory – same response at each encounter May destruct the antigen

Adaptive immunity Second level of defence Effectiveness increases with each encounter Specific immune response

Types of (adaptive) immunity Active Immunity Passive Immunity

Transfer of maternal antibodies Administration of antibodies

Active Immunity Antibodies produced in response to an infection Antibodies produced in response to a vaccination

Types of antibody IgG – the only type that crosses the placenta (after 32 weeks) IgA – in breast milk – gives some mucosal protection IgE – over production associated with anaphylaxis Also IgM – maybe further reading!

Active versus passive immunity ACTIVE Long lasting Takes time to be effective PASSIVE Only short term Immediate protection

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Vaccination schedule 2014 AgeDiseases protected against 2 monthsDiphtheria, tetanus, whooping cough, polio, Hib, pneumococcal disease Rotavirus 3 monthsDiphtheria, tetanus, whooping cough, polio, Hib, meningococcal disease type C and Rotavirus 4 monthsDiphtheria, tetanus, whooping cough, polio, Hib, pneumococcal & months Hib/meningococcal disease type C pneumococcal disease Measles, mumps & rubella (MMR) 3yrs 4mDiphtheria, tetanus, whooping cough, polio MMR (pre-school immunisations) 12-13yrsHPV (cervical cancer) girls only x doses over 6 month period 13-18yrsDiphtheria, tetanus, polio (school leavers immunisations) 16 Meningococcal type C booster from Sept 2013 (13-15 yrs)

Vaccine overload? Part of bodyBacteria Scalp1,000,000/cm 2 Surface of skin1000/cm 2 Saliva100,000,000/g Nasal mucus10,000,000/g FaecesOver 100,000,000/g

Contraindications Immunosuppression & treatment Some steroid use Unstable neurological condition Previous anaphylactic reaction Care with live vaccines Pyrexia Acute illness Side effects??

Vaccine trials Pre-clinical laboratory based work Phase I – (small scale – adults) Phase II – (population specific) Phase III – (100s-1000s participants) Phase IV  vaccines – MHRA reporting

Getting to the schedule Research and development JCVI Recommendations to DH Cost and feasibility studies Supply and delivery Awareness and training issues

References/further reading Immunisation against infectious disease (Green Book) [online] s/public-health-england/series/immunisation- against-infectious-disease-the-green-book s/public-health-england/series/immunisation- against-infectious-disease-the-green-book Health Protection Agency website