Pfizer and Moderna have promised to boost vaccine production in the coming months, as the country’s death toll from Covid-19 went past 500,000. Pfizer said the company will have 120 million doses of the vaccine available for shipment by the end of March and an additional 80 million doses by the end of May. Pfizer expects that all 300 million contracted doses - enough for up to 150 million Americans - will be available by the end of July. Moderna President Stephen Hoge plans to double vaccine production to over 40 million doses per month: 300 million doses will be ready by the end of July. The main concern is that new variants could become dominant in the US by March. A leading forecasting institute says over 90,000 more Americans are likely to die from Covid, and Americans will still be wearing masks in 2022.