Pfizer has committed to supply up to 40 million doses of its COVID-19 vaccine this year to a global effort to get affordable shots to poor and middle-income countries. The deal announced Friday will supply the shots to the program known as COVAX. It’s a boost to the global program, as wealthy nations have snapped up most of the millions of coming shots. Pfizer and its German partner BioNTech will provide the doses at an undisclosed but “not-for-profit price,” over the course of 2021. The doses are a small fraction of what’s needed, as COVAX aims vaccinate billions of people.