Moderna Inc on Monday raised the lower end of its 2021 forecast for COVID-19 vaccine production by 100 million doses.The company lifted it from 500 million doses previously to 600 million doses.Moderna said it is continuing to invest and add staff to build up to potentially 1 billion doses for 2021.The US-based pharma company said it expects about 100 million doses to be available in the country by the end of the first quarter of 2021, with 200 million doses total available by the end of the second quarter.Moderna, it its statement said that approximately 18 million doses have been supplied to the US government to date.The vaccine received Emergency Use Authorization from the US Food and Drug Administration (FDA) on December 18, 2020 and.