How Do They Do It?
What is an epitope
The part of an antigen to which an antibody attaches
What is the purpose/meaning of herd immunity
Herd immunity protects the whole community by reducing the chance of infection spreading from person to person.
What are the three diseases vaccinated against by the MMR vaccine
Measles, Mumps and Rubella
What are the main questions asked in Phase I of vaccine development?
Is the vaccine safe?
Does the vaccine work to cause the intended immune response?
What are the only human disease we've eradicated due to vaccination
(+bonus point for animal disease)
Smallpox
Rinderpest
What is an adjuvant in a vaccine
A compound that enhances the immune system's reaction to the antigen without itself providing immunity
How are anti-vaccination activists different from people who are vaccine hesitant or under-vaccinated, and what beliefs often cause anti-vaccine views?
Anti-vaccination activists oppose vaccines on purpose, while vaccine-hesitant or under-vaccinated people may just be unsure or lack access.
Anti-vaccine views often come from mistrust in medicine, conspiracy theories, and beliefs in “natural” living or personal freedom.
What is the R0 of Measles
15-18
How many participants are usually involved in Phase II of vaccine trials?
100-500 people
(accept up to 1000)
Outline some of the reasons the eradication of smallpox was made possible
No subclinical infections
Only one dominant variant of smallpox
Vaccine was highly effective at inducing sterile immunity
No animal reservoir
Vaccination was coupled with active surveillance and containment
What is a toxoid?
It’s a safe, inactive version of a toxin used in vaccines to teach the immune system to recognise and neutralise the real toxin later.
Give three common reasons why parents may choose not to vaccinate their children
Possible answers:
misinformation, fear of side effects, distrust of pharma/government, religious beliefs, complacency.
What event in the late 1990s caused a major drop in MMR uptake in the UK, and what was its basis?
The 1998 Andrew Wakefield study, which falsely linked the MMR vaccine to autism
What are the main aims of phase II of vaccine trials
Refining Dose
Confirming Safety
Checking consistency of immune response
What is used to treat the polio virus in inactivated polio vaccines
Formaldehyde
Which licensed vaccine/s use virus-like particles?
HPV and HepB
Virus-like particles are structurally similar to the virus but have no genetic material inside, so they can’t cause infection.
Why can higher-income countries sometimes have lower vaccine uptake than lower-income countries?
Because diseases become less visible in wealthy societies, leading to complacency and more focus on perceived vaccine risks, while lower-income countries still see the disease burden and value vaccines more
The MMR vaccine is typically given at these ages in the UK
1 year and 3 years 4 months
What made the COVID-19 vaccine timeline much faster than usual?
Give 2 reasons
Phases ran in parallel
Supported by global funding
Prior coronavirus research
Fast regulatory review.
What is the difference between
basic reproduction number R0 & effective reproduction rate Re
R₀ measures a pathogen’s infectiousness in a fully susceptible population with no immunity and no interventions, while Rₑ measures how many people it’s actually infecting, given immunity and control measures.
Explain how an mRNA vaccine stimulates immunity
1) The mRNA (in a lipid nanoparticle) is injected into the muscle.
2) The lipid coating helps the mRNA enter nearby body cells.
3) Inside the cell, the cell’s ribosomes read the mRNA and make the viral protein (e.g. spike protein).
4) The viral protein is shown on the cell surface or released into the body.
5) B cells make antibodies against the protein. T cells (helper and cytotoxic) are activated to attack infected cells.
6) Some B and T cells become memory cells, ready to respond rapidly if the real virus infects the body later.
What is the main reason HPV vaccination is so important?
Prevents infection by high-risk strains of HPV that cause cervical cancer and other diseases
To get the point - what are the two main strains responsible
The R component of MMR prevents this dangerous condition if infection occurs during pregnancy
Congenital Rubella Syndrome
After a vaccine successfully completes all the phases of clinical trials, what two major steps must occur before it can be offered to the public
Regulatory review and licensing by authorities such as the FDA or MHRA, to confirm safety, quality, and efficacy.
Policy recommendation by public health bodies (e.g., CDC or JCVI) deciding who should receive it and how it fits into vaccination programs.
A newly emerging viral infection has a basic reproduction number of 6.
1. Using the herd immunity formula calculate the minimum proportion of the population that must be vaccinated to achieve herd immunity.
2. Explain what would happen if only 60% of the population were vaccinated.
83.3%
population would not reach herd immunity, virus could still spread easily