WASHINGTON: America plans for "surge upon a surge" as many travelers have returned back home after the Thanksgiving holiday which may lead to a sudden boost in coronavirus cases, top US scientist Anthony Fauci warned Sunday. The US is the world's worst-affected country, and President Trump's administration has issued contradictory messages on mask-wearing, travel, and the danger posed by the virus. This week US airports have been busy as the travelers have surrounded after Thursday's Thanksgiving holiday since the pandemic began. US scientist, Fauci said," We may see a surge upon a surge. We don't want to frighten people, but that's the reality." The trend is dangerous, Fauci and other government scientists said, with the Christmas holidays sure to bring more travel and family gatherings. In the 24 hours to 0130 GMT Monday, the country added 140,651 coronavirus cases, taking its total to 13,373,673, according to Johns Hopkins University. There had been 822 additional deaths. Also, thousands of health workers marched in Madrid in support of Spain's public health system, in one of the European countries hardest hit by the pandemic. The US news media while reported that the first shipments of the Pfizer vaccine against coronavirus are one of the first to claim high effectiveness. The Pfizer and Moderna vaccines, both said to be safe and 95 percent effective, have introduced a glimmer of hope after months of gloomy news. Giroir said it might take until the second or third quarter of next year for most Americans to be vaccinated. The vaccinating firstly will be given to those at highest risk, he said, "we can absolutely get 80 percent of the benefit of the vaccine by only immunizing a few percent of the population." Also Read:- Iran will give a calculated response to scientist killing, Kamal Kharrazi Royal Enfield's Make-it-Yours keeps on the successful go President Trump alleges US elections were probably least secure ever