U.S. vaccine makers are ramping up production, tripling output in March to reach 132 million doses, according to the Wall Street Journal. Pfizer, together with BioNTech and Moderna have now scaled up production after a learning curve that led to a slower than expected rollout. Johnson & Johnson, which is new to the market, has teamed up with outside firms to increase their production, which should help speed up the nationwide campaign drive just as the threat of new deadly variants looms. Several states have reported a surge in cases despite vaccines being widely available. Around 2.5 million people in the US are vaccinated every day on average, up from 500,000 a day in early January.