Got a call on my cell phone from this number. The caller said she was representing the Center for Disease Controls and wanted to survey me about childhood immunizations. I asked what org she was calling with and she didn't have an answer and seemed flustered. I told her that wasn't a hard question and that I was suspicious and to remove my number from their list.

Received a call from 312-578-7017 at 8:46 p.m. today. Did not answer and caller left no message. When will the Fed's do something about these harrassors?

The phone number on the caller ID was NORC U Chicago, who indeed conduct research surveys for the CDC among others. Did not answer because I didn't know that till I looked it up. They didn't leave a message. But you can never really be sure who is calling, which is a shame because public opinion for surveys can be useful.

I just got a call from them. Same thing saying they were from the cdc

This number is a legit from CDC: http://www.cdc.gov/vaccines/imz-managers/nis/participant/index.html