Immunity and vaccines

• What is meant by herd immunity?

  Protection of unvaccinated individuals
• What are potential issues around vaccination?

  People choosing not to be vaccinated
• Why are vaccines widely used in medicine?

  To prevent epidemics and pandemics
• What is an epidemic?

  Rapid spread of disease in a population
• What is a pandemic?

  Rapid spread of disease across countries
• How did New Zealand experience an epidemic in 2019-2020?

  It had an epidemic of measles
• How are vaccines usually administered?

  Via mouth or injection into bloodstream
• What do vaccines contain to protect against pathogens?

  Antigens from the pathogen
• What type of vaccine contains a weakened strain of a pathogen?

  Attenuated vaccine
• What do inactivated vaccines contain?

  Killed bacterial cells or inactivated virus particles
• How do some vaccines trigger an immune response?

  By containing only antigen molecules
• What is the purpose of modifying toxin molecules in some vaccines?

  To make them harmless but act as antigens
• What happens when a vaccine enters the human body?

  It stimulates a primary immune response
• What do antibodies and memory B cells do after vaccination?

  They prepare the body for future infections
• What triggers the secondary immune response?

  Contact with the pathogen after vaccination
• What is produced rapidly during the secondary immune response?

  A large amount of antibodies
• What type of immunity does vaccination provide?

  Artificial active immunity
• What is herd immunity?

  Protection of unvaccinated individuals by vaccinated ones
• Why is herd immunity important?

  It protects those who cannot be vaccinated
• What happens if a significant number of people are not vaccinated?

  Herd immunity breaks down, leading to epidemics
• What routine vaccines are provided in the UK?

  The flu vaccine for those over 50
• How are vaccines used globally during pandemics?

  To control the spread of infectious diseases
• Why do people need to be re-vaccinated for influenza?

  Due to antigenic variability of the virus
• Why is there no effective vaccine for the common cold?

  There are over a hundred types of cold virus
• What are the steps of how vaccines work?

  1. Vaccines are administered via mouth or injection.
  2. They contain antigens from pathogens.
  3. They stimulate a primary immune response.
  4. Antibodies and memory B cells are produced.
  5. Secondary immune response occurs upon re-exposure.
  6. A large amount of antibodies is produced rapidly.
• What are the strengths and weaknesses of herd immunity?

  Strengths:

  • Protects unvaccinated individuals
  • Reduces disease spread in the population

  
  

  Weaknesses:

  • Requires high vaccination rates
  • Breaks down if many are unvaccinated