Vaccination

• What is the purpose of vaccination?

  To prevent illness in an individual
• How do vaccines work?

  Vaccines introduce small quantities of dead or inactive pathogens into the body
• What happens when the body is exposed to the dead or inactive pathogen in a vaccine?

  White blood cells produce antibodies against the pathogen
• Why can't the dead or inactive pathogen in a vaccine cause the disease?

  Because it is dead or inactive and cannot lead to the disease
• What happens to the white blood cells that produce antibodies against the pathogen in the vaccine?

  They divide by mitosis to produce many copies of themselves
• How do the white blood cells respond when the real pathogen enters the body later?

  They can quickly produce the correct antibodies to prevent infection
• Why is it important that a very large number of people are vaccinated?

  Because it provides herd immunity to protect unvaccinated people
• What is the term used to describe the protection provided to unvaccinated people when a large number of people are vaccinated?

  Herd immunity
• What are the key steps in how vaccines work to prevent illness?

  1. Vaccines introduce small quantities of dead or inactive pathogens into the body.
  2. White blood cells produce antibodies against the dead/inactive pathogens.
  3. The white blood cells divide by mitosis to produce many copies of themselves.
  4. If the real pathogen enters the body later, the white blood cells can quickly produce the correct antibodies to prevent infection.
• How do vaccines prevent the spread of pathogens in a population?

  • When a large number of people are vaccinated, it provides herd immunity.
  • Herd immunity protects unvaccinated people by reducing the spread of pathogens in the population.
  • This is because vaccinated people cannot transmit the pathogen to others, breaking the chain of infection.