6.1 DNA-based Vaccines
DNA vaccines provide a precise and flexible tactic to deliver antigens
to the immune system and can contain additional sequences of coding
molecules to manipulate the results (Rice et al., 2008). So far, a
variety of DNA vaccine platforms have been exploited to enhance the
vaccine efficacy through electroporation to deliver plasmids and
addition of adjuvants, yielding improved the immune responses (Sardesai
and Weiner, 2011). Inovio pharmaceuticals have begun pre-clinical trials
of a DNA vaccine (named as INO-4800) against COVID-19 (INOVIO, 2020).
This vaccine can induce T cell activation via transferring DNA plasmids
that express the SARS-CoV-2 S proteins (INOVIO, 2020). This vaccine
platform holds the preponderance of producing therapeutic antibodies and
activating immune cells to deliver the vaccine to patients through the
skin. With the support of CEPI, the corporation is making provision for
the first phase of trials in the United States and China (INOVIO, 2020).