Lecture 27 - Immunisation Flashcards
Benefits of immunisation?
immunity to infection, reduced disease in ALL people due to reduced transmission (herd immunity)
How we get protected?
protein antigens (T-cell-dependent antibodies), polysaccharide antigens (T cell-independent antibodies) live viral (antibodies, CD8 cytotoxic)
Classifications of vaccines?
live attenuated vaccines, inactivated vaccines (whole, fraction, toxoid, polysaccharide based, conjugate poysaccharide)
Live vaccine?
modify virus or bacteria in lab, replicate and produce immunity but not illness, lifelong immunity - can cause problems in immunocompromised people
Live vaccine e.g.?
viral: measles, rubella, oral polio, bacterial: BCG, oral typhoid, reassorted: rotavirus
Inactivated vaccines & whole e.g.?
repeated dose required; whole viral: influenza, polio, rabies and Hep A; whole bacterial: pertussis, typhoid, cholera
Fractional (component) vaccines?
subunits (hep B, influenza, acellular pertussis), toxoids (tetanus); requires multiple dosing but less antigen infection is preferred
Childhood vaccines - first?
Infanrix hexa - diphtheria, tetanus, acellular pertussis, inactivated polio, Haemophilus influenzae type B, hepatitus B; componenet antigens, 4x
Childhood vaccines - second?
MMR, all live, given @ 15 months and 4 years
Tetanus?
penicillin sensitive, gram positive, easily introduced to deep dirty injuries, 10 days after exposure demonstrates muscular rigidity, arched back, lock jaw (tetanospasm toxin)
Tetanus epidemiology?
elderly affected by declined immunity, neonatal tetanus high in developing world - passed from mother that has no access to immunisation (plan to give immunisations to all women of child-bearing age in high risk areas)
Passive immunisation - advantages?
immediate protection
Passive immunisation - disadvantages?
not long term, transmission risk of other disease from donor, expensive and not always readily available, expensive and not always available, serum sickness
Pertussis/whooping cough - catarrhal phase?
1-2 weeks, runny nose, conjunctival infection, malaise
Pertussis/whooping cough - paroxysmal phase?
1-10 weeks, short expiratory burst of rapid coughs, inspiratory gasp and high pitched whoop (followed by convalescent/recovery phase of weeks/months)
Pertussis complications?
secondary bacterial infections (pneumonia), encephalopathy, seizures, apnoea
Pertussis and antibiotics?
may shorten illness if given early and decrease infectivity but typically do little
Non-infants recommended for pertussis vaccination?
11-12yr booster, adults living with young children, adults working with children, health care workers (particularly of newborns)
Polio vaccines in NZ?
Injected killed version introduced 1956, oral vaccine introduced to completely lower cases (intestinal immunity), injected reintroduced post-2000
