Chinese companies are at the forefront of global efforts to create a vaccine for the coronavirus, with more than half a dozen candidates in clinical development. Last week, Tianjin-based CanSino Biologics published results1 from an early-stage clinical trial showing that its vaccine is safe and can trigger an immune response.
Yet the companies could face difficulty as they try to push vaccines through phase III trials, a crucial stage of testing that is needed to prove efficacy and secure approval from regulators. These trials usually require tens of thousands of participants, and with the outbreak in China largely under control, companies are having to test their vaccines elsewhere. But researchers say they might still struggle to enrol so many participants and employ enough health-care professionals to collect data.