Immunisation Flashcards
what caused the major fall in infant deaths in the 20th century
vaccination
who created vaccination
Edward Jenner
wha is an example of where vaccines can go wrong
1970s caused children to get side effect due to whooping cough vaccine not working properly
why do we have to be careful when giving a vaccine
- usefulness of having protection versus immune system development
what vaccine is given at
- two months old
- three months old
- four months old
- 12 month old
- diphtheria, tetanus, peruses, polio and haemophillus influenza type b, Meningitis type B, rotavirus, pneumococcal disease
- dipeteris, teatusmus, peruses, polio and hib, meninggoal C and B, rota virus
- diphtheria tetanus peruses polio hib, pneumococcal disease
- hib B/Men C, pneumococcal disease, measles, mumps and rubella
name some vaccines that you have to have if you have certain diseases (targeted vaccines)
BCG – neonatal depending on risk level (area/family)
Hepatitis B – In first year if born to infected mother
Influenza/pertussis – Pregnant women
what are some diseases that would mean you have to have vaccines earlier
Chronic respiratory, heart, neurological conditions
Diabetes
Haemophilia
Immunosuppressed (either naturally or drug-induced)
when can you not give a vaccine (important)
Anaphylaxis to a previous dose
Immunosuppression – do not give live vaccine (MMR, BCG)- some vaccines are weakened form so it can still cause an immune reaction
Pregnancy (in some cases) don’t give rubella while pregnant
Postpone if acutely unwell
several live vaccines can be given…
Several live vaccines can be given concurrently but if spaced, minimal interval = 3 weeks
why is it hard to make vaccines for some diseases
- in some diseases the pathogens infect and hide away having latent periods
- these are the diseases that we have problems making vaccines for
describe Herd vaccination
- this is when you vaccinate 85-90% of the population in order to prevent the spread of the disease and to protect the people that cannot be vaccinated for reasons such as being immunosuppressed
- if a lower amount of the population is vaccinated then it spreads further through eh population
how effective are vaccines
Vaccines have been so effective that many diseases are no longer seen in “rich” countries
why do parents withhold vaccination
Some parents may elect to withhold vaccination for fear of side effects, judging risk of vaccine to be higher than the small risk of catching infection
what diseases are hard to prevent through herd immunity
Highly contagious infections like chicken pox, whooping cough and measles more difficult to prevent through herd immunity
what are the features of an effective vaccine
safety protection longevity neutralising antibodies protective T cells practicality
describe the features of an effective vaccine
safety - the vaccine must not cause illness or death
protection - the vaccine must protect against exposure to the pathogen
longevity - the vaccine should give long lasting protection
neutralising antibodies - these must be induced to protect against pathogens such as polio, and many toxins and venoms
protective T cells - these must be induced to protect against pathogens such as TB
practicality - the vaccine must be cheap to produce and easy to administer
what are the reactions to vaccine administration
Anaphylactic reactions
Fever / febrile convulsion
Local reactions
Reversion of live vaccines to ‘wild type’
what are the problems of the vaccine when the pathogen is encountered
Vaccine ineffective
Heightened immune response to illness
what are the problems with vaccine and therefore the things that you must test
- reactions to vaccine administration
- problems when the pathogen is encountered
what is passive immunisation
- passive is when you receive antibodies
- an example would be the transfer of maternal antibodies from the mother to the baby
what is the difference between active and passive immunisation
passive involves receiving antibodies therefore the immune system is not activated whereas active is when you get some form of the disease thus the immune system is activated
name some types of active immunisation
- inactivated vaccines
- attenuated vaccines
- recombinant peptide vaccines
- DNA vaccines
- therapeutic vaccines
describe how passive antibodies are made
Injected killed pathogen Make ian immune response 10 days layer Take serum that contains the antibodies Inject mouse Challegne with live pathogen Shows animal is protected
what is passive immunisation used for
This type of immunisation is often given to counteract insect/animal venoms
what serum is usually used for passive immunisation
horse
what is the problem with passive immunisation and using horse serum
The immunisation effect lasts for as long as the antibody remains active – a few months at most
The patient makes an immune response against the serum (can cause “serum sickness”)
passive immunisation does not..
give long lasting protection
how is polio transmitted
Transmission: faecal – oral
what is polio caused by
enterovirus 3 different strains
Incubation period 7-14 days
what does polio have a high affinity for
nervous tissue
what is the inactivate and active form of disease of polio
inactive - polio Salk - sugar lump
active- polio sabin
describe polio Salk
- polio virus is marinated in formalin
- virus is unable to replicate thus it is deactivated
- generates good humeral immunity
- no chance of disease but has side effects
describe polio sabin
- a live weakend polio virus is generate
- the virus can replicate but does not cause diseae
- vaccine generates good humeral and cell mediated immunity
- occasionally can get polio in patients
why do we go inactivated, attenuated, inactivated in the case of polio
Injection - get rid of it the majority of it
Attenuated – stop spreading
Injected – prevent it coming back
name some inactivated vaccines
- DPT - Diphtheria, whooping cough, tetanus
- polio
- cholera
- influenza
- plague
name some attenuated vaccines
- MMR - measles, mumps and rubella
- polio sabin
- chicken pox
- tuberculosis
- influenza
- yellow fever
- rabies
what is a difference between inactivated and attenuated
- inactivated produces humeral immunity whereas attenuated produces humeral and cell mediated immunity
when was MMR introduce
Introduced to the UK in 1988
what are the side effects of MMR
malaise, fever, rash (at 1wk), febrile convulsions
what are the illnesses of MMR
Acute illness
Immunosuppression e.g. steroids, AIDS
Another live vaccine within previous 3 weeks
Receipt of immunoglobulin within previous 3 months
Children who have an anaphylactic reaction to egg should be immunised and observed in hospital for 2 hours
what is the cause and incubation period and pathogenesis of diphtheria
Notifiable illness caused by Corynebacterium diphtheria
Incubation period: 2-5 days
Pathogenesis: disease results from exotoxin-producing strains
what are the cause and incubation period of pertuses
Cause: Bordetella pertussis
Incubation period: 7-10 days
what are the adverse effects of pertusis vacciantion
Local: Redness and swelling
Systemic: Inconsolable screaming, high fever, hypotonic, seizures, anaphylaxis, bronchospasm
Encephalopathy (very rare, especially with new vaccine – 1.3/10 million
what causes tetanus, wha tis its incubation period and who is it transferred
Notifiable illness caused by Clostridium tetani (a spore forming anaerobic gram positive bacillus)
Incubation period of 4-21 days (depending on inoculum)
Transmission: direct transfer of spores (e.g. from soil)
what type of vaccine is tetanus
it is a toxoid
describe HpB symptoms
Many cases are asymptomatic, 1-2% develop fulminant hepatic failure with high risk of mortali
what are the two vaccines for HpB
Purified from human plasma – HBsAg
HBsAg produced in yeast cells by recombinant DNA technology
how effective is HpB
Vaccine is 90% effective after a 3-dose series (but this decreases over 40 years of age)
Duration of protection is at least 3-5 years – booster if concentration Antibody <50 IU/I
what type of pathogen is haemophilia influenzae type B
An encapsulated Gram negative bacterium which has been the major cause of bacterial meningitis and epiglottitis in infants and young children
describe how many people effected by haemophilia influenzae type B
70% of cases occur in children <2 years of age
1 in 600 develop disease by 5 years of age
An estimated 65 deaths/year in the UK prior to vaccine
describe the vaccine used for haemophilia influenzae type b
First vaccine consisted of purified polysaccharide PRP which was poorly immunogenic in children <2 years
We now have a conjugate vaccine (protein carrier) – highly protective
how does a recombinant peptide vaccine work
Get the virus sequence the gneome of the virus
Find a gene molecular clone it
Put it into a yeast
Purify the viral protein
Get lots of the protin and then use it as a vaccine – need to use it as an adjuvant
Makes a regulatory response – will not respond to that, desntities it
Mix the protein with harmless bactria and makes immune response to bacteria
describe benefits of adjuvants
- activate dendritic cells
- bias towards Th2 antibody response
- stimulate mucosal immunity
- bias towards TH1 cell mediated response
describe how a DNA vaccine works
- gene is isolated from pathogen
- placed in a bacterial plasma
- bacterial DNA acts as an adjuvant via TLR9
- add cytokines and the plasmid is then injected into the muscle of a recpipenet
- the animal is then protected
where do you inject DNA vaccines
they are injected into the muscle of a recipient
what is the future of vaccines
- this will occur when the animal is already infected and cannot clear the infection
- the sick animal is then vaccinated to boost the immune response and can now clear the infection
