Defensins are antimicrobial peptides that participate in the innate immunity of 
hosts. Humans constitutively and/or inducibly express α- and β-defensins, which 
are known for their antiviral and antibacterial activities. This review 
describes the application of human defensins. We discuss the extant experimental 
results, limited though they are, to consider the potential applicability of 
human defensins as antiviral agents. Given their antiviral effects, we propose 
that basic research be conducted on human defensins that focuses on RNA viruses, 
such as human immunodeficiency virus (HIV), influenza A virus (IAV), respiratory 
syncytial virus (RSV), and dengue virus (DENV), which are considered serious 
human pathogens but have posed huge challenges for vaccine development for 
different reasons. Concerning the prophylactic and therapeutic applications of 
defensins, we then discuss the applicability of human defensins as antivirals 
that has been demonstrated in reports using animal models. Finally, we discuss 
the potential adjuvant-like activity of human defensins and propose an 
exploration of the 'defensin vaccine' concept to prime the body with a 
controlled supply of human defensins. In sum, we suggest a conceptual framework 
to achieve the practical application of human defensins to combat viral 
infections.