Bacterial and Viral Vaccines Flashcards
Who first tested out the smallpox vaccine?
Benjamin Jesty - 1774
Edward Jenner 1796 (MORE POPULAR)
After the smallpox vaccine, when was the next vaccine made?
Almost 100 years later in 1885
What is the goal of immunisation?
To allow the body to protect itself from infectious diseases
What are the two types of immunity?
Innate
Acquired
What are the two types of acquired immunity?
Active - Made in own body
Passive - Ready made antibodies
What are the subcategories of active immunity?
Natural (disease exposure)
Artificial (Immunisation)
What are the subtypes of passive immunisation?
Natural - maternal antibodies
Artificial - exogenous antibodies
At what R0 (the no. of people 1 sick person can affect) is transmission halted?
If effective R0 is reduced < 1 then transmission is halted
What is herd immunity?
Form of immunity that occurs when vaccination of a significant proportion of a population provides a measure of protection for individuals that are not immune.
What is the Herd immunity threshold?
Percentage of fully immune individuals required to stop the spread of disease
How do you calculate the Herd Immunity threshold?
HIT = 1 -1/R0
What are the cells in the innate immune system?
Macrophage Dendritic cell Mast cell NK cell Granulocytes Complement proteins
Which cells are present in the adaptive immune response?
B cells - antibodies
T cells - CD4/CD8
What cells overlap between the innate and acquired response?
NK cells
gamma delta T cell
How does the body respond to a vaccine?
APCs present part of the antigen on the cell surface
APCs present antigen to naive T cells in the LN where they are activated
B cells activate in response to antigens - some B cells become plasma cells which produce specific antibodies and neutralise infection + Ab dependent cellular cytotoxicity
Attenuated Vx = T cell virus clearance
Memory cells produced
Does natural immunity occur after infection?
Microbial components give rise to a protective immune response
Vaccines need adjuvants to make it more potent
What are inactivated vaccines?
Whole microorganism destroyed
[by heat, chemicals, radiation or antibiotics (e.g. Influenza, cholera, polio)]
What are the advantages of inactivated vaccines?
- Stable
- Constituents clearly defined
- Unable to cause the infection
What are the disadvantages of inactivated vaccines?
- Need several doses
- Local reactions common
- Adjuvant needed
- Shorter lasting immunity
What are attenuated vaccines?
- Live organisms modified to be less virulent
- Examples
- Measles, mumps, rubella, yellow fever
What are toxoid vaccines?
Inactivated toxic components
Examples: Tetanus, diphtheria
What are subunit vaccines?
- Protein component of the microorganisms or synthetic virus like particles.
- Lacking viral genetic material and unable to replicate.
- Examples: Hepatitis B, HPV
What is a conjugate vaccine?
- Poorly immunogenic antigens paired with a protein that is highly immunogenic (adjuvant)
- Examples: Haemophilus influenzae type B
What is a heterotypic vaccine?
Pathogens that infect other animals but do not cause disease or cause mild disease in humans
• Examples: BCG
What is a viral vectored vaccine?
• Use a modified virus (e.g. adenovirus) to deliver
genetic code for an antigen.
• Examples: Ebola, Janssen and AZ COVID vaccines
What is a nucleic acid vaccine?
- Use DNA/RNA from the pathogen.
* Examples: Pfizer and Moderna COVID vaccines
What is the difference between monovalent and multivalent?
Mono = 1 antigen Multi = multiple antigen (e.g. pneumococcal which has 21 antigens)
What are the components of a vaccine?
Active components Adjuvants Antibiotics Stabilisers Preservatives Trace components
Serious reactions are uncommon
Serious reactions are uncommon
Why are vaccination programmes important?
• Vaccine should be administered before the age
related peak incidence of the disease.
• Targeted vs widespread.
• To eliminate a disease the effective R0 needs to be <1.
• ?requirement for catch up campaigns.
• Endemic vs Epidemic infections.
What are the barriers to vaccination?
Access
money
Anti vax campaigns
What are the prerequisites for successful disease eradication?
- No animal reservoir
- Antigenically stable pathogen with only one (or small number of) strains
- No latent reservoir of infection and no integration of pathogen genetic material into host genome
- Vaccine must induce a lasting and effective immune response
- High coverage required for very contagious pathogens
Do vaccines have a good impact?
Yes
What are the side effects of vaccines?
- Adenoviral vectored vaccines
- VITT
- 14.2 per million doses
- CLS
- Pfizer
- Lymphadenopathy
- Myocarditis
