3.7&8 immunisation & clinical trials

• What is the aim of vaccination?

  To induce production of T and B lymphocytes
• What do T and B lymphocytes produce in response to vaccination?

  They produce antibodies
• What is a primary immune response?

  The initial response to a pathogen by the immune system
• What type of cells remain after the primary immune response?

  B & T Memory cells
• What is the role of memory cells in the immune response?

  They provide a faster secondary immune response
• What is an adjuvant?

  A substance that enhances the immune response
• Why are antigens mixed with adjuvants in vaccines?

  To make the vaccine more effective
• What is herd immunity?

  • Occurs when a large percentage of a population is immunised
  • Reduces the spread of diseases
  • Protects non-immune individuals
• What protects non-immune individuals in a herd immunity scenario?

  Lower probability of contact with infected individuals
• What factors determine the herd immunity threshold?

  The type of disease, vaccine effectiveness, population density
• Why is establishing herd immunity important?

  It reduces the spread of diseases in the community
• What challenges can affect herd immunity in developing countries?

  Poverty and malnourishment limit vaccination programs
• What can cause herd immunity to break down in developed countries?

  Adverse publicity about vaccine safety
• What is the herd immunity threshold?

  The proportion of individuals that need to be immune
• What happens if the herd immunity threshold is reached?

  The disease decreases to a low baseline level
• What is the role of antigenic variation in pathogens?

  Some pathogens change their antigens
• Why can some diseases not be eradicated by vaccines?

  Pathogens evolve mechanisms to evade the immune system
• What is immunisation?

  The process of becoming immune to a disease
• How does immunisation stimulate the immune system?

  By administering a vaccine that triggers antibody production
• What is a double-blind trial?

  Neither patient nor doctor knows the treatment
• Why is randomisation important in clinical trials?

  It eliminates bias in group assignments
• What is a placebo?

  A dummy treatment with no active ingredient
• What is the placebo effect?

  Feeling better due to believing in treatment
• What is artificially acquired immunity?

  Immunity developed from vaccination
• What forms can antigens in vaccines take?

  Inactivated toxins, dead pathogens, weakened pathogens
• What are the different forms of antigens used in vaccines?

  • Dead pathogens (e.g., Polio, Hepatitis A)
  • Weakened pathogens (e.g., Measles, Mumps, Rubella)
  • Parts of pathogens (e.g., Hepatitis B, HPV)
  • Inactivated toxins (e.g., Tetanus, Diphtheria)
• What is the purpose of booster vaccinations?

  To ensure long-lasting immunity
• What is the effect of antigenic variation in influenza?

  It requires annual vaccinations for at-risk individuals
• How do clinical trials establish the safety of vaccines?

  By testing them before licensing for use
• What is the importance of group size in clinical trials?

  Larger groups reduce experimental error
• What is the purpose of a randomised clinical trial?

  To ensure fair and valid testing
• What happens at the end of a clinical trial?

  Results are compared for statistical significance
• What is the role of the immune system in vaccination?

  To protect against subsequent infections
• How do vaccines stimulate the immune system?

  By exposing the body to antigens
• What is the significance of the herd immunity threshold?

  It indicates the level of immunity needed
• What can happen if herd immunity is not maintained?

  Increased number of new disease cases
• How does antigenic variation impact vaccination strategies?

  It necessitates annual vaccinations for certain diseases
• What is the impact of adverse publicity on vaccination rates?

  It can lead to lower vaccination compliance
• What is the purpose of mass vaccination programs?

  To create herd immunity against diseases
• What is the relationship between poverty and vaccination programs?

  Poverty limits the ability to implement programs