Forget for a moment that Bill Gates founded Microsoft. Forget that Gates now chairs a philanthropic foundation that works in a number of areas. During his keynote session at the mHealth Summit in Washington DC this week, Bill Gates arrived with a single, focused message: Vaccines.

When asked whether mobile phones offered some advantages over previous computing platforms, Gates responded:

"Computing technology has been great for healthcare, but primarily on the research side," Gates explained. "That is: Anything that facilitates the invention of new vaccines is fantastic. That is the miracle intervention in healthcare on a worldwide basis. Although it would be hard to measure, some combination of the Internet, digital databases, collaboration tools, really have changed medical research. Although in the drug field in the last decade, research hasn't been that great. In the areas that are of particular interest to the poor -- AIDS, drugs, and vaccines -- it's actually been a period of great productivity. So in that indirect sense there is a lot of impact."

"In the case of the cell phone there is a chance to go beyond that and actually be there with the patient in the clinic, which may or may not be staffed with a fully-trained doctor," Gates said. "There are a lot of opportunities. I think we have to approach these things with some humility though. There are not Internet and data connections [everywhere] out there. People... in most cases when they're sick, are often too sick for some cell phone type services to do something for them. I do think there is absolutely some role, but I think we need to hold ourselves to some pretty tough metrics to see if we are really making a difference or not."

When pushed for specific examples of the (potentially) most impactful mobile health services, Gates discussed the dramatic reduction in infant and child mortality since 1960: It went from 20 million to about 8.5 million.

"That's been achieved -- about a third of it -- by increasing income, which gives you better nutrition, better living conditions. The majority of it has been done through vaccines," Gates said. "Smallpox was killing 2 million a year, now it kills zero per year. Measles was killing 1.5 million, now it kills about 300,000 a year."

So where do mobile phones fit in to the vaccines discussion? Gates asked that same question. Then he answered it:

"If you could register every birth on the cell phone, get fingerprints, get a location, then you could take these systems, go around and make sure the immunization happens," Gates said. "Then you could run them in a more effective way. Vaccine coverage in the very poorest regions like the north of Nigeria and north of India are below 50 percent."

In areas like those healthcare providers could see a huge improvement if they manage to "just take the vaccines we have today" and make sure they get delivered.

Bill Gates, the founder of Microsoft and chair of the Bill & Melinda Gates Foundation sees the greatest opportunities for mHealth in and around vaccine delivery and tracking. Or maybe since he's become so laser focused on the issue he sees how mobile can help. When prompted, Gates made a passing remark about PHR platforms like Google Health and Microsoft HealthVault and was dismissive about mHealth's potential to motivate those that exercise "zero percent" to get off the couch.

While Gates' vision for mHealth seemed fairly limited on-stage, his blog post the day following his appearance at the mHealth Summit showed a different side. After discussing various point of care diagnostic sensors enabled by mobile technology, he concluded his post on mobile health like so: "Cell phones are amazing tools. For some of us, they’re about staying in touch. For millions of people, it could be about staying alive."