Vaccination

• What is a vaccine?

  A way of introducing antigens of a dead or weakened pathogen to stimulate antibody production.
• How does one dose of a vaccine affect the immune system?

  It induces a primary immune response.
• How do multiple doses of a vaccine affect the immune system?

  They increase the number of antibodies and memory cells in the bloodstream.
• Why do vaccines provide long-lasting immunity?

  Because they produce memory cells.
• What do some vaccines contain to protect against different strains or diseases?

  Multiple antigens.
• How are pathogens in vaccines made harmless?

  By killing or weakening the pathogen while leaving antigens unaffected or creating a source of antigens only.
• What is attenuation in vaccines?

  Weakening the pathogen by heating it.
• What are toxoids in vaccines?

  Inactivated toxins that trigger the same immune response.
• Why do some people experience mild symptoms after vaccination?

  Because vaccines contain foreign antigens, which can trigger a primary immune response.
• What are some ethical issues related to vaccines?

  Animal testing, clinical trial risks, refusal due to side effects, and difficult decisions on vaccine distribution.
• What is herd immunity?

  When enough people are vaccinated they are immune and cannot be infected so it prevents the pathogen from spreading widely in a population.
• How does herd immunity protect people who cannot be vaccinated?

  It prevents the pathogen from spreading to them because most people around them are immune so cannot become infected.
• Why don't vaccinations fully eliminate diseases?

  Immunodeficiency, slow primary response, antigenic variability, multiple strains, objections to vaccination.
• What is active immunity?

  When the body makes antibodies after exposure to an antigen through the primary immune response.
• What is natural active immunity?

  Immunity after catching a disease.
• What is artificial active immunity?

  Immunity after receiving a vaccination with harmless antigens.
• What is passive immunity?

  When the body is given antibodies made by another organism.
• What is natural passive immunity?

  A baby receives antibodies through the placenta or breast milk.
• What is artificial passive immunity?

  An injection of antibodies or a blood plasma transfusion, e.g. against tetanus toxin.
• Why is passive immunity short-term?

  Because no memory cells are produced as no immune response occurs.
• How do maternal antibodies protect babies?

  By passing through the placenta or in breast milk.
• Why is protection from maternal antibodies temporary?

  Antibodies are broken down in the spleen and liver, and no memory cells are formed.