Vaccination and Herd Immunity

• What should you be able to describe by the end of this video?

  How vaccines reduce disease spread
• 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 epidemic did New Zealand experience in 2019-2020?

  Measles epidemic
• What is a pandemic?

  Rapid spread of disease across countries
• What pandemic was mentioned in the study material?

  COVID-19 pandemic
• How are vaccines usually administered?

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

  Antigens from the pathogen
• What is an attenuated strain in vaccines?

  A weakened strain of a bacterium or virus
• What happens when a vaccine containing killed bacterial cells is administered?

  The pathogen cannot cause an infection
• How do some vaccines trigger an immune response?

  By containing inactivated virus particles
• What are antigen molecules in vaccines?

  Extracted or genetically engineered from pathogens
• How do some vaccines provide protection against toxins?

  By containing modified toxin molecules
• What is stimulated when a vaccine enters the human body?

  A primary immune response
• What do antibodies and memory B cells do?

  Help fight off future infections
• What triggers the secondary immune response?

  Contact with the pathogen after vaccination
• What happens during the secondary immune response?

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

  Artificial active immunity
• What is herd immunity?

  Protection for unvaccinated individuals in a population
• What happens if a significant number of people are not vaccinated?

  Herd immunity breaks down, leading to epidemics
• What routine vaccine is provided free in the UK?

  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. Vaccine enters the body
  2. Stimulates primary immune response
  3. Antibodies and memory B cells produced
  4. If exposed to pathogen later, secondary immune response occurs
  5. Rapid production of antibodies destroys pathogen
• What are the strengths and weaknesses of herd immunity?

  Strengths:

  • Protects unvaccinated individuals
  • Reduces disease spread in the community

  
  

  Weaknesses:

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