Impact of the pandemic on vaccine technology
In recent years, there have been significant efforts in developing other types of vaccine against infectious diseases, such as nucleic acids (DNA and RNA) and viral vectors. Until several months ago, none of these new vaccines were approved by US FDA. However, during the pandemic, government-facilitated COVID-19 vaccine development has since resulted in US FDA’s approval (emergency use authorization) of some of these new types of vaccine in a matter of months. This truly remarkable achievement also serves as a touchstone for clinical feasibility of these new types of vaccine, including the DNA vaccines PBI has been developing. The new and effective COVID-19 vaccines (including the two mRNA vaccines, and a DNA vaccine licensed in India) work primarily by producing virus-specific antibodies that recognize and neutralize viral particles on mucosal surfaces and in blood (humoral immunity). Once the virus establishes active infection, these circulating and secreted antibodies are not as effective as viral replication occurs intracellularly. In contrast, PBI’s recombinant vaccines work primarily by inducing virus-specific cytotoxic T lymphocytes that recognize and destroy virally infected cells (cellular immunity).