The makers of the coronavirus vaccines are pushing to distribute 240 million doses in the U.S. by the end of March.

Pfizer and Moderna have pledged to have a combined 220 million doses available for shipment.

Pfizer says it will start shipping more than 13 million per week by the middle of March. And Moderna plans to ship more than 40 million per month, by April.

Johnson & Johnson has pledged to make 20 million doses available in the same time frame. And this shot only requires one dose. An FDA committee is meeting Friday to discuss Johnson & Johnson's vaccine.