DNA may offer rapid road to Zika vaccine

Last August, scientists injected a potential vaccine for Zika virus into a human being — just 3½ months after they had decided exactly what molecular recipe to use. In the world of vaccine development, 3½ months from design to injection is “warp speed,” says vaccine researcher Nelson Michael of the Walter Reed Army Institute of Research in Silver Spring, Md. Clinical trials can take years and epidemics can burn out before vaccines make it to doctors’ shelves. Even vaccine creation is typically sluggish. But in this case, the vaccine is a bit of DNA, which means scientists can get moving fast. Unlike some traditional methods, DNA vaccines don’t use dead or weakened viruses. Instead, they rely on a snippet of genetic material. This “naked” DNA carries, for example, the blueprints for Zika proteins. It’s just a long sequence of DNA blocks. With DNA vaccines, “it’s easy to move very quickly,” says Anthony Fauci,...