Immunisation Flashcards
What is an immunisation
Immunisation is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine.
Vaccines stimulate the body’s immune system to protect the person against subsequent infection or disease
Aim of ideal vaccine
To produce the same immune protection which usually follows natural infection but without causing disease
To generate long-lasting immunity
To interrupt spread of infection
what is immunity
The ability of the human body to protect itself from infectious disease
Body’s Defence Mechanisms what do they include and what do they mean
Complex-
Innate (non-specific, non adaptive) mechanisms
Acquired (specific, adaptive) systems
Innate or non-specific immunity
Present from birth
Physical barriers (intact skin, mucous membranes)
Chemical barriers (gastric acid, digestive enzymes)
Phagocytic cells
Defining characteristic: No memory persists afterwards
Acquired immunity
Generally specific to a single organism or a group of closely related organisms
Two basic mechanisms for acquiring immunity:
passive
active
Passive immunity
Transfer of antibodies from immune individuals
Most common across the placenta
Less often from blood transfusion
Protection cross-placental more effective against some infections (e.g tetanus and measles) than for others (e.g. polio and whooping cough)
Temporary protection ( only lasts few weeks or months)
Active immunity
Protection produced by an individual’s own immune system
Usually long lasting
Acquired by natural disease or vaccination
Selective vaccination
Just given to those at increased risk
Travel
E.g. Japanese B encephalitis
Occupational risk
E.g. anthrax
High risk groups
E.g. Hepatitis B vaccine for healthcare workers
Mass vaccination
Either:
Eradication of a diseaseDisease and its causal agent have been removed worldwide e.g. smallpox
Elimination
Disease has disappeared from one WHO Region but remains elsewhere e.g. polio
Containment
The point at which the disease no longer constitutes a “significant public health problem”
How vaccines work
Induce active immunity and provide immunological memory
Immunological memory – enables immune system to recognise and respond rapidly to natural infection at a later date
Can prevent or modify the disease
Inactivated vaccines
First injection produces a primary antibody response (IgM)
Two or more may be needed to give this response in young infants
This is the primary course
Further injections lead to an accelerated response - the secondary response (IgG – remain after infection has passed)
Live vaccines
Live attenuated virus vaccines - e.g. MMR usually promote a full, long-lasting antibody response after one or two doses
To produce immune response, the live organism must replicate in the vaccinated individual
Will not cause the disease itself
Could be over period of time (days or weeks)
Vaccine failure
No vaccine offers 100% protection
A small number of individuals get infected despite vaccination
Primary failure - individual fails to make an immunological response
Secondary failure - individual responds initially but protection wanes over time
Timing of Vaccine Reactions
Inactivated vaccines: generally within 48hrs following vaccination
Live vaccines: occur according to time taken for virus to replicate
e.g. MMR vaccine:-
measles component (malaise, fever, rash) tend to occur in 1st week following vaccination
rubella component (pain, stiffness or swelling of joints) tend to occur in 2nd week following vaccination
mumps component (parotid swelling) tend to occur in 3rd week following vaccination (although may occur up to 6 weeks following vaccination)
Vaccine Reactions
Fever can be expected after any vaccination
Common when MenB given with other vaccines at 8 and 16 weeks
Paracetamol given to reduce risk of fever, irritability and general discomfort
Three doses of paracetamol can be given following vaccination
2.5ml of paracetamol 120mg/5ml as soon as possible after vaccination
Second dose after 4 to 6 hours
Third dose 4 to 6 hours after the second dose
Herd immunity
Only applies to diseases passed from person to person
For each disease there is a certain level of immunity in the population which protects the whole population because the disease stops spreading in the community
A disease can therefore be eradicated even if some people remain susceptible
Herd immunity provides indirect protection of unvaccinated as well as vaccinated individuals. This may be the most important aspect of how they work. For example, MMR given to infants protects pregnant women from rubella.
Draw the vaccine schedule table
on whiteboard!!
4-in-1 pre-school booster
Given from 3 years and 4 months up to starting school
Single jab containing vaccines against diphtheria, tetanus, pertussis and polio
HPV vaccine
Given to boys and girls between 12 and 13 years old
Two injections given between six months and two years apart
Human papilloma virus vaccine protects against cervical cancer
Around 970 women died from cervical cancer in 2011- estimated about 400 lives could be saved each year through vaccination
3-in-1 vaccine
Given between 13 and 18 years of age
Single jab, diphtheria, tetanus and polio
Men ACWY vaccine
Given around 14 years of age (school year 9)
Also given to students going to University for the first time
Vaccination to protect against 4 different causes of meningitis and septicaemia A,C,W and Y
Influenza
symptoms
Aching muscles
Fever
Too unwell for daily activities – usually in bed
Symptoms develop quickly
influenza transmission
Airborne transmission
Contact transmission
Droplet transmission
