QuickTake: Viruses mutate all the time, including the novel coronavirus that’s caused the global Covid-19 pandemic. Most of the changes have no apparent effect. But recent variants that have emerged in the U.K., South Africa and Brazil are causing particular concern. They don’t appear to be any more virulent than earlier strains, but studies suggest they are more contagious. An increase in infections has led to a surge in hospitalizations and deaths in England and elsewhere. Drugmakers say their vaccines should still work, but some researchers warn the shots may need to be updated periodically to maintain their efficacy. The variant that emerged in southeast England in September, dubbed the B.1.1.7 lineage, contributed to a spike in cases in December that sent the U.K. back into lockdown. It also prompted many places, including the U.S., to halt air and train travel from the U.K. or impose restrictions. Other countries have followed with tighter lockdowns, particularly in Europe, and continue to urge people to take precautions like wearing masks. Health officials have warned the strain could become dominant in the U.S. as soon as March. In southern Africa, hospitals are facing pressure from a resurgence driven by another variant, 501Y.V2. Brazilian researchers are warning that a so-called P.1 variant spotted in Manaus, Amazonas state, in December could be aggravating an outbreak there. Four Japanese travelers returning from Amazonas in early January were found to have the virus during routine screening at Tokyo’s Haneda airport. Researchers at Cedars-Sinai Medical Center in Los Angeles say a novel strain has emerged in California, though less is known about its importance. FULL QUICKTAKE: https://bloom.bg/39PTLJc Subscribe to our YouTube channel: https://bit.ly/2TwO8Gm Bloomberg Quicktake brings you live global news and original shows spanning business, technology, politics and culture. Make sense of the stories changing your business and your world. To watch complete coverage on Bloomberg Quicktake 24/7, visit http://www.bloomberg.com/qt/live, or watch on Apple TV, Roku, Samsung Smart TV, Fire TV and Android TV on the Bloomberg app. Have a story to tell? Fill out this survey for a chance to have it featured on Bloomberg Quicktake: https://cor.us/surveys/27AF30 Connect with us on… YouTube: https://www.youtube.com/user/Bloomberg Breaking News on YouTube: https://www.youtube.com/c/BloombergQuickTakeNews Twitter: https://twitter.com/quicktake Facebook: https://www.facebook.com/quicktake Instagram: https://www.instagram.com/quicktake