Vaccines work wonders. They prevent disease from striking, which is better than treating it after the fact. They are also relatively cheap and easy to deliver. Yet millions of children do not get them. This has always been stunning to me. When we started the Gates Foundation 15 years ago, we assumed that all of the obvious steps were already being taken, and that we would have to go after the expensive or unproven solutions. In fact, delivering basic vaccines is still one of our top priorities.

As I look ahead to 2014, I am more optimistic than ever about the progress that we can make using the power of vaccines to give all children — wherever they live — a healthy start to life. We have new resources from generous donors worldwide. We are developing new and better vaccines to protect kids from deadly diseases. And we are finding innovative ways to deliver them, especially in hard-to-reach areas.

One of the most exciting — and often overlooked — developments in the global push to give all children access to immunization is the growing role of emerging-country vaccine suppliers. Countries like Brazil, China and India have faced many health and development challenges of their own, and they have made tremendous progress. Now they are using their experience and technical capacity to help other countries make similar progress.