Vaccination: The Principles Flashcards
why do we use vaccines
- can prevent the spread of infectious disease
- creates herd immunity to reduce the spread of infectious disease
- protects people who cann be vaccinated such as young babies and those who have compromised immune systems
How do vaccines work
Vaccines safely deliver an immunogen which is a specific type of antigen that elicits an immune response, to train the immune system to recognize the pathogen when it is encountered naturally.
How can vaccines be delivered
- infection into the muscle
- infection under the skin
- oral route
Why do vaccines require more than one dose
- build a complete immunity
- give a booster dose when the immunity wears off
- immunize people against viruses causing disease that may be differnet from season to season for example the yearly flu vaccine
What are vaccine preventable diseases
- Infectious disease for which an effective preventivie vaccine exists
What is a vaccine preventable death
- this happens if a person acquires a vaccine-preventable disease and dies from it, the death is considered a vaccine-preventable death
Name the most common and preventable serious vaccine preventable diseases
- Diphtheria
- haemophilus influenzae serotype B infection
- hepatitis B
- measles
- meningitis
- mumps
- pertussis
- poliomyelitis
- rubella
- tetanus
- tuberculosis
- yellow fever
How do vaccines work
Herd immunity
describe how herd immunity works
- Vaccinations protects unvaccinated people as well as vaccinated because with fewer infected people in the populaiton there will be les sopportunity for susceptible people to be infected
What is the obejctive of vaccination
- eradicate the infection throughout by herd immunity
What is the reproductive number
- The number of secondary cases infected by one index case in a susceptible population on average
What does the R number increase with
- population density, longer infectivity, respriatory spread
To reach herd immunity how much of the population has to be vaccianted
75%-90% of the population
Name the types of vaccines
- Attenuated live virus
- whole inactivated virus
- protein subunit
- recombinant
- peptides
- replicating or non replicating viral vectors
- nucleic acid
What are the advatnages and disadvantages of attenuated live virus
Advantage
- induces the same response as natural infection
Disadvantge
- not recommended for pregnant women and immunocompromised persons
Name some examples of attenuated live virus vaccines
- measles
- rubella
- mumps
- yellow fever
- smallpox
What are the advantages and disadvantages of whole inactivated virus
Advantages
- induces strong antibody response
Disadvantages
- requires large quantities of virus
Name some examples of whole inactivated virus vaccines
- influenza
- rabies
- hepatitis A
What are the advantages and disadvantages of protein subunit vaccines
Advantages
- may have fewer side effects than whole virus (redness, swelling at injection site)
Disadvantages
- May be poorly immunogenic
- complex process
Name some examples of protein subunit vaccines
- Influenza
What are the advantages and disadvantages of recombinant vaccines
Advantage
- no need to produce the whole virus
Disadvantage
- may be poorly immunogenic
- high cost
What are the examples of recombinant vaccines
- Hepatitis B
What are the advantages and disadvantages of peptides
Advantages
- rapid development
Disadvantage
- poorly immunogenic
- high cost
what are the examples of peptides
- COVID-19 vaccines in development
What are the advantages and disadvantages of replicating or non replicating viral vectors
Advantages
- rapid development
Disadvantage
- prior exposure to vector virus
- may reduce immunogenicity
What are the exampels of replicating or non replicating viral vectors
- Ebola
What are the advantages and disadvantages of nucelic acid
Advantages
- strong cell immunity
- rapid development
Disadvantages
- relatively low antibody response
What are the examples of nucleic acid
- covid-19 vaccines in development
How are viruses given as a vaccine
- selective, modified, or completely inactivated so it will not cause disease
How are protein based vaccines given
= A protein is extracted from the virus ( alive or inactivated) they are then purified and injected as a vaccine
How do viral vector vaccines work
- The gene for a pathogen protein is inserted into a different virus that can infect someone without causing disease
- The safe virus serves as a ‘platform’ or ‘vector’ to deliver the protein that triggers an immune response
- The safe virus is then injected as a vaccine
- Somereplicate (reproduce) in the body and some do not
How do nucleic acid vaccines work
- Instead of a virus, a protein antigen, or a virus expressing the protein, nucleic acid coding for the antigen is injected
- DNA plasmid:enters nucleus, translated to mRNA for expression of protein
- Or mRNA can be injected.More direct (no translation required) but less stable than DNA
What book has the latest information on vaccines and vaccination procedures for all the vaccine preventable infectious diseases that may occur in the UK
The green book
Describe the UK immunisaiton programme
8 weeks
- Diptheria, tetanus, pertusis, polio, Hib and hepatitis B
- pneumococccal conjugate vaccine
- meningococcal B
- rotavirus
12 weeks
- Diptheria, tetanus, pertusis, polio, Hib and hepatitis B
- rotavirus
16 weeks
- Diptheria, tetanus, pertusis, polio, Hib and hepatitis B
- pneumococccal conjugate vaccine
- meningococcal B
One year old
- Hib/MenC booster
- pneumococcal conjugate vaccine booster
- meningococcal B booster
- MMR
three years four months - Diptheria, tetanus, pertusis, polio
- MMR
12-13 years old
- HPV
14 years old
- tetanus, diphtheria adn polio
- Meningococcal ACWY
65 years old
- pneumococcal poolysaccharide vaccine
65 years of age and older
- inactivated influenza vaccine
70 years old
- shingles
What is diphtheria caused by
• Diphtheria is an infection caused by the bacterium Corynebacterium diphtheriae.
What happens in diphtheria
Diphtheria causes a thick covering in the back of the throat. It can lead to difficulty breathing, heart failure, paralysis, and even death
What causes tetanus
Tetanus is a serious illness caused by Clostridium bacteria
- bacteria can enter the body through a deep cut
Where does the tetanus bacteria live
soil, saliva, dust, and manure.
What can tetanus cause to happen
- infection can cause painful tightening of the muscles
What is the vaccine used for in tetanus
Toxoid adsorbed onto an adjuvant
what can cause pertussis
- is a highly contagious respiratory disease.
* It is caused by the bacterium Bordetella pertussis.
What happens in pertussis
• Pertussis is known for uncontrollable, violent coughing often makes it hard to breathe
What causes meningitis
The bacterium Neisseria meningitidis, also
called meningococcus,
causes meningococcal meningitis.
What does haemophilus influenza type B cause
- responsible for severe pneumonia, meningitis and other invasive diseases
How is haemophilus influenza type B transmitted
• Transmitted through the respiratory tract from infected to susceptible individuals
What type of vaccine is haemophilus influenza type B
Hib vaccine as a polysaccharide conjugate vaccine, which is a type of inactivated bacterial vaccine.
what is penumococic
• Pneumococci are a type of streptococcus bacteria. (Streptococcus Pneumonieae)
How does pneumocci spread
• Spread through contact with people who are ill or by healthy people who carry the bacteria in the back of their nose.
What are the vaccines for pneumoccocus
- Pneumococcal conjugate vaccine or PCV13
* Pneumococcal polysaccharide vaccine or PPSV23
What is the most common cause of diarrhoea
- Rotavirus - this is the most common cause of severe diarrhoeal disease in young children throughout the world
What are the four differnet type of vaccines for rotavirus
Four oral, live, attenuated rotavirus vaccines available internationally:
• RotarixTM (derived from a single common strain of human rotavirus);
• RotaTeqTM (a reassorted bovine- human rotavirus);
• RotavacTM (naturally occurring bovine-human reassortant neonatal G9P, also called 116E);
• RotaSiilTM (bovine-human reassortant with human G1, G2, G3 and G4 bovine UK G6P[5] backbone)
What organ does hepatitis B attack
- Hepatitis B is a viral infection that attacks the liver
* Can cause both acute and chronic disease
How is hepatitis B transmitted
- from mother to child during birth and delivery,
* through contact with blood or other body fluids
What does MMR protect against
- Measles
- mumps
- rubella
When do you have the MMR vaccine dose
- within a month of their first birthday
- 3 years and 4 months
what type of vaccine is the MMR
live-attenuated (weakened) live virus vaccine
Why is MMR not given until the age of 12-15 months
- because passively acquired maternal antibodies would destory the live vaccine if given under 1 year
what two HPV viruses cause cancer
16 and 18 = these cause cervical cancer
What two HPV viruses cause gential warts
6 and 11 = these cause genital warts
What happens in polio disease
The virus spreads from person to person and can invade an infected person’s brain and spinal cord, causing paralysis
What vaccine is used in polio disease
Killed virus absorbed onto adjuvants (oral live vaccine used in some countries)
what does the oral polio vaccine contain
Oral polio vaccine (OPV) contains an attenuated (weakened) vaccine-virus
what can happen with the oral polio vaccine
- On rare occasions, if a population is seriously under-immunized, an excreted vaccine- virus can continue to circulate for an extended period of time.
- In very rare instances, the vaccine-virus can genetically change into a form that can paralyse – this is what is known as a circulating vaccine-derived poliovirus (cVDPV)
What does BCG stand for
Bacillus Calmette–Guérin (BCG) vaccine
What is BCG used against
- tuberculosis
Who is the BCG recommended for
BCG vaccination is only recommended on the NHS for babies, children and adults under the age of 35 who are at risk of catching tuberculosis (TB)
Which babies get the BCG vaccine
BCG vaccination is recommended for all babies up to 1 year old who:
• are born in areas of the UK where the rates of TB are high
• have a parent or grandparent who was born in a country where there’s a high rate of TB (high risk = incidence of TB >40/100,000)
Define vaccine efficiacy
% reduction in disease incidence in a vaccinated group compared to an unvaccinated group under optimal conditions (eg RCT)
How effective are vaccines
All are 96% to 100% effective except: • Pertussis 75% • Pneumococcus 60% • Rotavirus 60% • Influenza 75% • BCG 70%
How long does the immunity of vaccines last
- All give lifelong immunity except:
- Influenza = 1 year
- Pneumococcal = 5 years
How many vaccines have herd immunity
Herd immunity applies to all these vaccines except:
• Tetanus - is caught from bacteria in the environment, not from other people who have the disease
• Influenza - High antigenic shift and drift
• TB–organisms constantly reintroduced
• Pertussis (Efficacy<80%)
• Rotavirus (Efficacy<80%)
• Pneumococcal (Efficacy<80%)
What are the 4 main adverse events following immunisation
● programme-related ● vaccine-induced
● coincidental
● unknown.
What can adverse effects following immunisation be caused by
AEFIs may be true adverse reactions that are intrinsic to the vaccine, or may be caused by the way it is administered or be related to an underlying condition in the recipient.
- can also be coincidental and would have occured regardless of vaccination
Who should you avoid giving a vaccine in
●● history of a confirmed anaphylactic reaction to a previous dose of the vaccine
●● history of a confirmed anaphylactic reaction to a component of the vaccine
●● primary or acquired immunodeficiency
●● current or recent immunosuppressive or immunosuppressive biological therapy
●● infants born to a mother who received immunosuppressive biological therapy during pregnancy
●● those in contact with an individual with immunodeficiency, current recent immunosuppressive including biological therapy
●● pregnant women
Name routine vaccination given in pregnancy
- Pertusis vaccination is given in mothers who are 28 weeks + pregnancy
- cases of pertusis are occuring in the first few weeks of life before the vaccine
- influenza
What vaccinations are given in young adults
- Influenza - people with chronic illness
- BCG
- pneumococcal
- varicella
- Hepatitis A and B - people at higher risk only
describe the influenza vaccine
- Live attenuated strains of the three most endemic influenza viruses that year (killed virus in adults)
• New versions of the vaccines are developed twice a year, as the influenza virus rapidly changes.
Who should get the flu vaccination
- Elderly people
- Diabetics
- Patients with chronic lung
- Heart
- Renal disease
- Immunosuppressed patients
- Healthcare personnel
How effective is the infleunza vaccine
On average the efficacy of the vaccine against the targeted strains is about 75%.
Name the adverse events that can follow immunisation
- pain, swelling or redness at the site of injection. These occur commonly after immunisation and should be anticipated
- local adverse reactions that generally start within a few hours of the injection and are usually mild and self-limiting.
- these are often referred to as ‘hypersensitivity reactions’, they are not allergic in origin, but may be either due to high titres of antibody or a direct effect of the vaccine product,
- Rash with MMR – common
- Systemic adverse reactions which include fever, malaise, myalgia, irritability, headache and loss of appetite.
- Limpness,cyanosis–Rare
- Anaphylactic reactions to vaccines are extremely rare but have the potential to be fatal. – no deaths as a result of the reaction
