1 Department of Pediatrics and Molecular Virology and Microbiology, National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, USA; Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, Houston, TX, USA; James A. Baker III Institute for Public Policy, Rice University, Houston, TX, USA; Department of Biology, Baylor University, Waco, TX, USA. Electronic address: hotez@bcm.edu.