Emerging Frontiers in Vaccine Development: A Review of Changing Paradigm

The technology behind vaccine development varies significantly from one vaccine to another depending on the time when the vaccine was first developed. Over the years, the vaccine innovation time has significantly shortened with the advancement of knowledge in the fields of molecular and cell biology, and discoveries in the field of biotechnology. The first vaccines created were tested in a kind of trial-and-error approach which sometimes had deadly side effects. These vaccines used either living, weakened, or completely dead pathogens. The use of whole pathogen vaccines was seen to be time consuming and unpredictable because even though it would cause an immune response, it could vary from person to person, and always had the risk of pathogens returning to virulence causing sometimes fatal outcomes. The next major technology used to create vaccines was subunit vaccines which utilize purified antigens inactivated through various methods. This technology is quite prevalent among the vaccines that are currently in circulation, making them quite effective, and free from fatal side effects. The viral vector vaccine technology has been around for a few decades and utilizes knowledge of molecular genetics to the greatest extent. It uses intermediate vectors to deliver genetic instructions to trigger an immune response within the subject body. The introduction of nucleic acid vaccines is the newest technology and has come to a great deal of attention during the SARS-CoV-2 immunization efforts. The technology primarily utilizes the delivery of genetic information using messenger ribonucleic acid (mRNA) to create characteristic pathogen-specific proteins that in turn generate an immune response in the recipients.