COVID-19 vaccine makers told Congress on Tuesday to expect a big jump in the delivery of doses over the coming month, and the companies insist they will be able to provide enough for most Americans to get inoculated by summer. By the end of March, Pfizer and Moderna expect to have provided the U.S. government with a total of 220 million vaccine doses, up sharply from the roughly 75 million shipped so far. … That’s not counting a third vaccine, from Johnson & Johnson, that’s expected to get a green light from regulators soon.