immunity and immunisation

  • innate

    • non-specific, non adaptive

      • polymorphonuclear luecocytes (neutrophils)

      • macrophages

      • complement

    • kill microbes without any prior exposure

    • interact with lymphocytes

      • induce cascade of events

  • acquired

    • specific, adaptive

      • B lymphocytes

        • plasma cells

          • serete antibodies

        • memory

          • long lived

          • rapidly proliferate and secrete large amounts of antibody

      • T lymphocytes

        • T helper

          • directors

        • cytotoxic T lymphocytes

          • killer

  • goal of immunisation = prime and prepare immune system

    • respond rapidly and specifically

      • prevent/attenuate

        • disease

        • colonisation

        • infection

  • Active immunity

    • generated by host’s specific immune system

    • primary immune response

      • plasma cell

        • IgM -> IgG

      • first response = slow and peaks d30

    • secondary immune response

      • plasma cell

        • IgG

          • peaks 4-7d

  • Passive immunity

    • deosn’t depend on recipient’s immune response for protection

    • temproary

    • weeks - months

    • injection of human IG

      • TIG

      • ZIG

      • HBIG

      • Rabies IG

    • breast milk

  • reproduction number - R0

    • number of secondary cases generated by a typical infectious indiviual when rest of population susceptible

    • must be above 1 to remain to exist

      • else can be eradicated

  • Herd immunity threshold

    • proportion of immune individuals ina population that must be exceeded to prevent disease transmission

    • 1-1/R0

  • target = 95% of children to be fully immunised by age 8mo then 2yr

  • vaccination:

    • types

      - live microbes - attenuated

      - MMR/varicella

- rotavirus

- attenuated vaccine virus multiplies to a limited extenet

    - induces immune response similar to wild virus infection

- usually very effective

- vaccines

    - MMR

    - varicella

    - rotavirus

    - zoster

    - BCG

      • whole microbes killed

        • treat whole cell/birus with chemicals

          • inactivation

        • organisms remain intact

        • cannot cause an infection

          • cannot reproduce

      • fragments

        • toxoid

          • some bacterial infections = toxins rather than organisms

          • alter toxin -> toxoid

          • induce antibodies that neutralise exotoxin

        • Recombinant

          • HepB/HPV

          • gene from pathogen

            • antigen -> response

          • pure vaccine that is efficient to produce

        • Polysaccharide and conjugate vaccines

          • poorly immunogenic

          • low affinity antibodies

            • do not ilicit T-cell responses

          • should have maximum 3 doses lifetime

          • children \<2yo shouldn’t receive polysaccharide

            • ineffective

    • administration ilicits immune response

      • innate

        • stimulate adaptive

    • immune memory can last for many years - often life

      • may wane

      • booster = stimulate memory cells producing more antibodies

    • Vaccination ingrediants

      • adjuvants

        • enhance immune response

          • aluminum hydroxide

      • preservatives

      • stabilisers

        • sucrose, lactose, albumin

        • surfactants/emulsifierspolysorbate 80

      • residuals

        • include virus inactivating agents

        • antibiotics

        • egg protein

        • gelatin

Contraindications

  • general contraindications:

    • anaphylaxis to previous vaccine dose

    • Live viral vaccines should not be given to pregnant women nor to immunosuppressed

  • precautions

    • acute febrile illness

      • minor infection without signifiant fever or systemic upset no reason to delay

      • should be postponed if fever >38

    • reaction to previous dose

    • allergy to vaccine components

      • egg

        • not CI to MMR

        • no longer considered CI to influenza

    • thrombocytopenia/bleeding disorder

      • administer with caution

      • 23G or smaller

      • can give SC - except hepB

    • avoid giving 2 different live parenteral virus vaccine within 4 weeks of each other

      • antibody response may interfere

        • TIG

          • 3mo

        • ZIG

          • 5mo

        • RBC - washed

          • 0

        • RBC packed

          • 5mo

        • plasma/platelet

          • 7mo

  • NOT CONTRAINDICATIONS

    • temp \<38

    • atopy

    • treatment with abx or locally acting steroids

    • breastfeeding mum/child

    • neonatal jaundive

    • low wieght in otherwise well

    • child being over usual age

    • previous hypotonic-hyporesponsive episode

    • ghistory of vaccination disease

    • prematurity in otherwise well

    • stabel neurological conditions

    • egg allergy

      • no longer CI to MMR

    • fhx

    -

cold chain maagement

  • stored at +2 - +8degC at all times

  • must use pharmaceutical refridgerator

  • monitor with electronic temperature recording device

    • records and doenloads data on a monthly basis

  • they have achoice

  • why being offered

  • what is involved

  • probable benefits, risks, side-effects, failure rates and alternatives

  • risks and benefits of not receiving treament

checklist

  • unwell

  • fever >38

  • ever had a severe reaction before

  • severe allergies to vaccine compents

    • gelatin

    • egg

    • neomycin

  • appropriate spacing

  • prgnant/planning pregnancy

  • undiagnosed or evolving neuroloigcal condition

Giving vaccine

  • skin prep

    • not necessary

    • etoh may inactivate live attenuated vaccine

    • IM

      • MMR = SC

      • rotavirus = oral

Common vaccine responses:

  • DTaP

    • localised pain

    • mild fever

    • grizzly unsettled - 24-48hrs

    • drowsiness

    • extensive limb swelling after 4th dose

  • Hep B

    • very occ. soreness and redness at injection site

    • mildfever

  • MMR

    • discomfort at injection site

    • 5-12 days:

      • mild fever with faint rash (not infectious)

      • head cold/runny nose

      • cough and / or puffy eyes

      • swelling of salivary glands

  • adult Td

    • localised discomfrot

    • redness and swelling

  • influenza

    • mild fever

  • pneumococcal

    • pain

  • HPV

    • localised discomfort

    • heavy arm

    • mild fever

    • nausea

    • dizziness

    • headache

Hypotonic-hyporesponsive episode

  • sudden onset of pallor/cyanosis, limpness and reduced responsiveness

    • no other cause

  • 1-48hours after vaccination

  • resolves spontaneously

  • Adrenaline not recommended

    • don’t have respiratory and circulatory problems

  • report to CARM

Antivaccination

  • take concerns seriously

    • respond appropriately with as much infomration as possible

  • explore reasons for antivaccination

    • personal experience

    • philisophical beliefs

    • dissatisfaction

  • people take on board what makes sense to them

  • people are unlikely to vaccinate if they perceive that there is little risk of disease; anad that vaccines are not safe and do not work

  • Themes:

    • ‘cover up’ - information suprressed to keep true facts hidden

    • ‘excavation of the facts’ - evidence against immunisation cna be found if searched for

    • ‘unholy alliance for profit’

    • ‘towards totalitarianism’ - increase state control

    • ‘us and them’

    • ‘poisonous cocktails’

      • highly regulated

      • aluminium

        • noramlly all aluminium excreted through urine

        • foods = 10-15mg aluminium/day

      • mercury

        • NO VACCINES ON NZNIS contain THIOMERSAL

    • ‘cause of idiopathic illnesses’

      • MMR: no evidence MMR causes autism

      • allergic disease (asthma)

        • 2005/2012 cochrane review no evidence MMR

      • SUDI

        • chance

      • overload/overwhelm infant immune system

        • multiple microbial challenges in the environment

    • ‘back to nature’ - natural is better than man-made

      • natural immunity may last longer

        • both are protective

      • immunity for Hib \<2yo, HPV, tetanus = better compared to natural infection

  • disease is not serious

  • healthy children can and do still die from these diseases; and many more would do so if it were not for vaccination

  • disease is uncommon

  • disease is common in unimmunised populations and can easily recur and spread if immunisation rates drop

  • vaccine is ineffective

  • need to have studies showing effectiveness prior to introduction of vaccine

  • immunity wanes following natural infection

  • duration = variety of factors

  • subunit vaccines require primary courses and boosters

  • polysaccharide do not generate long-lived memory cells

  • if interval = short; duration of immunity can be affected - why minimum intervals required

  • in very young and very old - immune persistance limited

  • ‘most cases are in immunised children’

  • 100 children

  • 90% immunisation with 90%efficacy

  • 81/100 immune

  • 10 susceptible b/c not having vaccine

  • 9 b/c vaccine failure

  • vaccine is unsafe

  • need to be tested

  • homeopathy

  • no scientific evidence that supports homeopathy for preventing disease