CNN  —  Scientists in Germany say they’ve been able to make a nasal vaccine that can shut down a Covid-19 infection in the nose and throat, where the virus gets its first foothold in the body. In experiments in hamsters, two doses of the vaccine – which is made with a live but weakened form of the coronavirus that causes Covid-19 – blocked the virus from copying itself in the animals’ upper airways, achieving “sterilizing immunity” and preventing illness, a long-sought goal of the pandemic. Although this vaccine has several more hurdles to clear before it gets to a doctor’s office or drug store, other nasal vaccines are in use or are nearing the finish line in clinical trials. China and India both rolled out vaccines given through the nasal tissues last fall, though it’s not clear how well they may be working. Studies on the effectiveness of these vaccines have yet to be published, leaving much of the world to wonder whether this approach to protection really works in people. The US has reached …