Flu scientists are hoping to vaccinate themselves against another outbreak of a crippling controversy. In a letter published this week by Nature and Science (see p. 612), 22 researchers make their case for launching potentially risky experiments with the H7N9 avian influenza virus, which emerged earlier this year in China and which some scientists fear could spark a deadly human pandemic. The scientists, who mostly work in U.S.-funded labs, also detail the safety and security precautions that they would take to prevent the possibly dangerous viruses they create from escaping from the lab—or falling into the hands of terrorists. In...