Were Vaccines Really the Cause of the Eradication of Smallpox?

(Image obtained from: https://pixabay.com/photos/cows-curious-cattle-agriculture-1029077/). The information below was paraphrased from a transcript of an interview with Suzanne Humphries which can be found in the following link. Development of the smallpox vaccine took place long before anything was known about the immune system. Many people died after receiving the smallpox vaccination. Many people developed serious smallpox