“Are Vaccine-Preventable Illnesses Dangerous and Deadly?” Sources
Death rate declined by nearly 90% before the introduction of the U.S. vaccine program: https://static1.squarespace.com/static/5d0301718520ae000165cc5b/t/65562e8816327d56724af034/1700146825506/Did+Vaccines+Save+the+Day+C24.pdf; https://www.cdc.gov/nchs/data/vsus/vsrates1940_60.pdf
CDC says decrease in illness was due to improved water sanitation: https://www.cdc.gov/healthywater/drinking/history.html
Vax Facts: What to Consider Before Vaccinating at All Ages & All Stages of Life by Paul Thomas, M.D. and DeeDee Hoover