Vaccines are urgently needed to protect vulnerable individuals and populations from disease. For arthropod-borne (arbo)viruses only few vaccines are currently available. Live attenuated vaccines consisting of weakened virus strains are among the most cost-effective strategies to prevent pathogen transmission and spread. One safety requirement for live attenuated vaccines against mosquito-borne viruses is that they should not be able to replicate in mosquitoes to prevent unintentional spread of vaccine-derived virus variants. In this project the researchers designed a universally applicable module to prevent replication of arboviruses in mosquitoes. The researchers modified viral genomes in such a way that a small RNA molecule of the mosquito targets the viral genome for degradation. This modification reduced virus replication in the mosquito but did not affect replication in mammalian cells. Introducing the module into live-attenuated viruses is expected to increase safety of live attenuated arbovirus vaccines.
