Vaccination still remains the most widely used method of controlling infectious diseases in both humans and animals. In view of this, considerable research effort is being devoted to the discovery of new vaccines, and to the refinement of existing ones, with the aim of making them safer, cheaper, and above all, more efficacious. Among the novel developments in vaccine technology is the use of naked DNA encoding the relevant immunogenic component of pathogens, which has been shown to confer protection on animals. Several advantages, such as stability, stimulation of both cellular and humoral immune responses, and antigen expression over prolonged periods, make DNA vaccines an attractive alternative to conventional ones. This paper highlights the progress made so far with the new technology in terms of its immunogenicity, concerns regarding its safety, and future research directions.
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