The headlines have been full of the latest “breakthroughs” in efforts to develop a vaccine against COVID-19, and markets have even reacted to all the twists and turns in recent weeks. Although he understands the desire for any positive news in the midst of a deadly pandemic, Michael Kinch, associate vice chancellor and director of the Center for Research Innovation in Biotechnology at Washington University in St. Louis, is keen to temper expectations about a vaccine. He notes that the history of vaccines is filled with arduous trial-and-error, and explains why “layering our defenses” against the new coronavirus may be our best shot.