That's interesting. Perhaps that's true for a certain number of public health schools, but as I'm perusing some of the school websites, many of them do not have an mph requirement. In fact, the PhD application process seems to generally be with a separate department, e.g. graduate admissions, rather than directly through the public health school (more geared towards masters admissions).
Here are the schools that I saw did not require a previous MPH degree.
- Harvard (offered through graduate school of arts and sciences)
- Emory Epi PhD program (offered through Rollins School of PH)
- Columbia (PhD no previous MPH needed, offered through graduate school of arts and sciences, or DrPH, which does requires a MPH)
I think the question of whether or not an MPH is required for admissions depends on the program/department you're applying to. If you're seeking to do research in public health, there's no reason for you to need an MPH prior to admissions.
With regards to the funding, this is taken from Emory's PhD admissions page:
TUITION AND FELLOWSHIPS
Doctoral students accepted into Epidemiology are awarded full tuition support (valued at $29,800) and an annual stipend (Fellowship) of $15,800 guaranteed for 4 years. Students receive stipends on a 9- or 12-month basis. Additional fellowships may be available for students with a research interest in reproductive, pediatric and perinatal epidemiology. In addition, an additional fellowship may be available for students interested in environmental epidemiology.
What I mean is that assuming you're doing the PhD for research reasons, then had you been admitted to the PhD program in the first place, most schools would have paid for your entire education. How do they fund for it? Through the government grants that they receive for research!! Those billions of dollars don't just go to pipettes... =)
This, I only learned of AFTER having decided to apply to MPH / MHA programs. Had I known, I may have very well chosen the PhD route.
Some PhD students (including a friend of mine in an unrelated field), may end up finding that the PhD route isn't suitable for them and opt to 'drop out' of the program after two years and after having received their 'masters' in that field... what one of my friends did. So in a way, he received his masters for free.
Given that though, the schools aren't stupid. They're seeking students who ACTUALLY want to go through with the PhD, the lab hours, the dissertation, all that can extend the Doctoral process beyond the supposed 4 years. So unless you demonstrate this in your application, which generally includes some sort of shortened, watered down research proposal, you won't get in anyways.
Again, I'm not an expert with this entire process, so my best recommendation again is to speak to your current adviser. He/She should, emphasis on should, be able to guide you in terms of switching your degree intentions and finding funding for it.