A codon-pair deoptimized live-attenuated vaccine against respiratory syncytial virus is immunogenic and efficacious in non-human primates

Despite a critical need for a respiratory syncytial virus (RSV) vaccine and decades of development efforts, a vaccine to protect infants, elderly, and other at-risk populations from RSV infection remains elusive. We have previously generated a new, live-attenuated vaccine candidate against RSV using rational, computer-aided gene design and chemical synthesis through a process termed viral gene deoptimization. In this study, we assessed the attenuation, immunogenicity, and efficacy of this synthetic, live-attenuated RSV vaccine candidate, RSV-MinL4.0, in African Green Monkeys. RSV-MinL4.0 was produced under good-manufacturing-practice (GMP) in Vero cells. Vaccination with RSV-MinL4.0 resulted in minimal virus shedding after vaccination, generation of robust humoral and cellular immune responses (despite the presence of baseline RSV neutralizing antibodies in one animal) that were comparable to a wildtype infection, and protection from virus shedding post-challenge with wildtype RSV. These findings demonstrate the promise of RSV-MinL4.0 as a live-attenuated vaccine which will undergo clinical trials to test its ability to safely and effectively protect pediatric and elderly populations from infection with RSV. (C) 2020 Elsevier Ltd. All rights reserved.