By Nikhila Natarajan New York, Jan 22 : Dr. Anthony Fauci is back. After months of being sidelined and attacked by Donald Trump, America's top infectious diseases expert returned to the White House briefing room and declared that the US could return to "a degree of normality" by the Fall if the Covid-19 vaccination campaign goes well this summer. The ambitious project is the Joe Biden administration's biggest challenge and remains a big 'if' because of "vaccine hesitancy", as Fauci put it. Achieving widespread or "herd" immunity would require vaccinating as many as 280 million people. Vaccines from Pfizer and Moderna are currently in the mix, Johnson and Johnson now has sufficient data from its late-stage vaccine trial to crunch the data soon. "If we can get 70 to 85 per cent of the country vaccinated by the end of... middle of the summer months, we could approach a degree of normality by Fall," was Fauci's assessment of a best case scenario for the US as things stand right now. A little more than 17 million doses have been administered as on January 21. The Trump administration had talked up a goal of vaccinating 20 million before the end of December 2020. Fauci's remarks come on a day when US President Joe Biden announced his goal of vaccinating 100 million people in 100 days and signed off on 10 executive orders all aimed at jumpstarting his national Covid-19 strategy. Biden also released a 198 page document on how his administration plans to get a handle on the pandemic's deadly surge. "We didn't get into this mess overnight, and it will take months to turn this around," Biden said at the White House. US deaths have surged past 400,000, and a University of Washington predictive model notes that the numbers could reach 500,000 in a month. Biden has directed the Federal Emergency Management Agency to begin setting up vaccination centers, so that at least 100 can be operational in a month in large spaces which are typically available inside locations like schools, sports facilities and convention centres. The Centers for Disease Control and Prevention has been asked to help get vaccines available at pharmacies starting next month. Biden has set a goal of having K-8 schools open safely in his first 100 days. It is now one full year after Covid-19 arrived in the US -- the first case was reported on January 21, 2020 -- and the virus is nowhere close to being finished with the country. More than 404,000 Americans are dead, more than 24 million have been infected. Biden has promised to "manage the hell out of this operation", setting an ambitious agenda that includes a national mask mandate, swift vaccinations and direct payments to people hurting from the economic collapse. /IANS