Although today’s vaccines are safer, more effective, and more accessible than they were even 20 years ago, the emergence of new, complex pathogens has exposed limitations in traditional vaccine strategies. Viral vector vaccines (VVVs) hold great promise for confronting those now-intractable pathogens. Combining the best features of live-attenuated and DNA-vaccine approaches, these next-generation prophylactics seek to harness the infectivity of non- or low-immunogenicity viruses to shuttle antigen-encoding DNA from target pathogens into host cells. The resulting transduced cells then initiate…