This blog provides a brief summary of pros and cons of three different platforms used for vaccine development. (a) Conventional vaccine, (b) Viral Vector based vaccine (C) Nucleic acid vaccine
Conventional vaccine
Conventional vaccine use live attenuated or inactivated pathogens responsible for the disease such as monkey pox. This technology has been beneficial against several infectious diseases in the past. But carries the risk of reversion and severe adverse effects, in particulars for highly pathogenic organisms. Furthermore, commercial production of this type of vaccine is challenging because of cultivation of whole pathogen posing biosafety risks. Additionally, full characterization of new pathogen requires time so this technology may not be practical during outbreak situations because of time constraints as seen during COVID-19 pandemic.
Viral vector-based vaccine
viral vector-based vaccine, however, can compensate the risk and time disadvantages of conventional vaccines. The viral vectors are used to encode heterologous antigens that use host cells as production factories. Antigens delivered to host cells are expressed inside cells that triggers immune response. This platform appeared to be effective against variety of pathogens such as Ebola virus, Zika virus. However, the concerns for viral vectors use include being genetically modified organisms and the risk of integration into the host genome, by persistent replication in the host cells.
Nucleic acid vaccine
Nucleic acid vaccines, both DNA and RNA vaccines, presents more advanced platform with significant benefits over conventional vaccines. Nucleic acid vaccines are easy to manufacture and customize to accommodate multi antigens and to compensate mutation in the pathogen. This type of vaccine can induce both humoral and cellular immune responses. This type of vaccines also have an edge over the viral-vector-based vaccines because they are derived from recombinant plasmids of bacterial origin. Therefore, a persistent replication and host genome integration, is less likely. Furthermore, the FDA has recommended that the termination of a study is not required if plasmid DNA remains below 30,000 copies per µg of host DNA. As a matter of fact, RNA vaccine was the first one that provided relief during COVID pandemic sufferings.
In summary, conventional vaccines may be the old tested and tried method for vaccine development but with modern tools of molecular biology tools available to researchers, viral vector and nucleic acid technologies are the future vaccine arena.
Reference
Chaube, Ruchi. “Vaccine Against SARS-CoV-2: Challenges and Considerations.” Canada Communicable Disease Report 47.3 (2021)ProQuest. Web. 30 Sep. 2022.