How does the current state of public health compare to the concerns and recommendations of public health professionals of the past?

How does the current state of public health compare to the concerns and recommendations of public health professionals of the past?
What is an example of a health issue that has improved as a result of public health interventions? Which theories or models support this success?
What is an example of a health issue that has notimproved as a result of public health interventions? Which theories or models explain why things have not changed?