Vaccines targeting the highly transmissible delta variant may now be needed, given its ability to infect people with fading immunity and potentially increased severity, researchers leading a large English study of Covid shots said. A third wave of English cases has been driven by the delta strain among both unvaccinated people -- especially those aged 12 to 24 -- as well as some people who had received Covid shots, according to authors of a study of samples from about 98,000 people in England. The effectiveness of vaccines at stopping infection during the study period fell to 49%, the researchers estimated, down from 64% in a month earlier. Vaccines’ protection against development of Covid symptoms was 59%, down from 83%. “Development of vaccines against delta may be warranted,” in the light of evidence that the strain’s spike protein has mutated to a point where antibodies raised by current shots are becoming less effective, the researchers said. Subscribe to our YouTube channel: https://bit.ly/2TwO8Gm Subscribe to our newest channel Quicktake Explained: https://bit.ly/3iERrup 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