Vaccines and the decline in infectious disease rates

(A comment made in response to a vaccine debate on Facebook.)

Improved standards of living and sanitation are attributed with reducing infectious disease rates in developed countries. Antibiotics have also reduced their severity and death rates. Infectious disease rates were in steep decline before vaccines became common. I have yet to see a study that attempts to quantify what portion of infectious disease reduction is due to vaccines and which is due to other factors, such as improved living standards (diet, housing, plumbing, etc). Therefore, there appears to be no real intelligent argument for vaccine effectiveness that I can see, as we don't have the proper studies to prove anything. http://sharkasnotes.blogspot.com.au/2017/08/the-only-meaningful-science-on-vaccines.html