"Also, can anybody explain why the CDC doesn’t mandate reporting?" Because a great deal of this is done at the state level. Working on these kind of problems,

"Also, can anybody explain why the CDC doesn’t mandate reporting?" Because a great deal of this is done at the state level. Working on these kind of problems, there's a very difficult balance of reporting requirements, agreed upon definitions (especially not just what you have but where you got it), various stakeholders, etc. And the CDC collects a lot of data even if things are universally reportable. And there's a lot of ongoing improvement.