Immunisation Flashcards
how does immunisation control communicable diseases
prevent onset of disease (primary prevention)
interrupt transmission
alter course of infection/disease to prevent or limit consequences (secondary prevention)
give examples secondary prevention immunisation
immunoglobulin e.g. Hep B, rabies, varicella zoster
how do vaccine work
teaches immune system to recognise pathogens, which helps to fight them
induce cell mediates immunity responses and serum antibodies
what are the immunity mechanisms
active immunity
passive immunity
herd immunity
what usually makes up antigens
usually proteins or polysaccharides (sugars)
how are antibodies produced
B cells- humoral immune system
T cells- cell mediated immune system (CD4+ and CD8+ cells)
where do B cells mature
bone marrow
where do T cells mature
in the thymus
what is passive immunity
transfer of pre-formed antibodies (immunoglobulins)
what are the mechanisms of passive immunity
mother to unborn baby (via placenta)
from another person or animal (blood donors, human normal Ig, specific Ig)
what are the two passive immunity vaccines
human immunoglobulin- Hep B, rabies, varicella zoster
anti-toxin- diphtheria, botulinum
what are the advantages of passive immunity vaccines
rapid action, post exposure, can attenuate illness, outbreak control, can be used if contraindication to active vaccination
what are the disadvantages of passive immunity vaccines
short term protection, short term window, blood-derived, hypersensitivity reaction, expensive
what are the mechanisms of active immunisation
natural infection, artificial immunisation
what are the two types of vaccine
live virus vaccines- attenuated organism replicates in host
inactivated vaccines- suspensions of killed organisms, subunit vaccines, conjugate vaccines
give examples of live virus vaccines
OPV (polio), measles, mumps, rebella, varicella, rotavirus, flu
give examples of inactivated viruses that are suspensions of killed organisms
whole cell pertussis, whole cell typhoid
give examples of inactivated viruses that are subunit vaccines
toxoids (diphtheria toxoid, tetanus toxoid, pertussis toxoid)
polysaccharides (pneumococcal, typhoid)
give examples of inactivated viruses that are conjugate vaccines
polysaccharide attached to immunogenic proteins - Hib, Men C
what are the contraindications to vaccines
confirmed anaphylaxis reaction to previous dose
live vaccines- immunosuppression, pregnancy
egg alergy (yellow fever, flu)
severe latex allergy
acute or evolving illness
what is the role of herd immunity
protects unvaccinated individuals through having sufficiently large proportion of population vaccinated
vaccinated stop the transmission of the organism
what does herd immunity depend on
transmissibility and infectiousness of organism
social mixing in the population
requires that there is no other reservoir of infection