[Campbell Biology P.1017] According to the text, which observation was crucial to Edward Jenn... | Practice Question

According to the text, which observation was crucial to Edward Jenner's development of immunization against smallpox?

  • A: That cowpox was a far more dangerous disease than smallpox, requiring immediate intervention.
  • B: That milkmaids who had previously contracted cowpox did not subsequently contract smallpox.
  • C: That inactivated bacterial toxins could be used to stimulate an immune response against viral diseases.
  • D: That injecting weakened smallpox pathogens could induce adaptive immunity without causing severe disease.

Explanation

The text explicitly states that Edward Jenner noted 'milkmaids who had cowpox, a mild disease usually seen only in cows, did not contract smallpox, a far more dangerous disease.' This observation led him to use the cowpox virus to induce immunity against smallpox, forming the basis of vaccination.