What Are Vaccines? #39

• What is the main topic of the video?

  How vaccines work and their pros and cons
• What happens to our immune system after exposure to a pathogen?

  It generally develops immunity to that pathogen
• Why do we only catch chickenpox once?

  Because we develop immunity after the first infection
• What is the problem with naturally catching diseases?

  It can range from unpleasant to lethal
• What do vaccines allow us to do?

  Expose ourselves to pathogens without catching diseases
• What do vaccines contain?

  Weakened or inactivated pathogens
• How does the body respond to the weakened pathogens in vaccines?

  It produces antibodies and develops immunity
• How many diseases have vaccines been developed for?

  More than a dozen diseases
• What is one major pro of vaccines?

  They protect us from catching horrible diseases
• What larger scale effect do vaccines have?

  They help control diseases that were common
• What are some diseases that vaccines have helped control?

  Polio, smallpox, measles, whooping cough
• What is an epidemic?

  A rapid spread of disease across a population
• What is herd immunity?

  When enough people are immune to a pathogen
• How does herd immunity help prevent disease spread?

  It reduces the number of hosts for the pathogen
• What happens to a pathogen when the host overcomes the disease?

  The pathogen disappears if there are no hosts
• What is a common problem with vaccines?

  They don't always grant full immunity
• What do we generally check after receiving an important vaccine?

  If it has been effective
• What are some bad reactions to vaccines?

  Swelling, fevers, or seizures
• How common are bad reactions to vaccines?

  They are pretty rare
• How common are severe reactions to vaccines?

  They are super rare