Chronicles, Classes, Constituents, and Creation of Traditional Vaccines and COVID-19 Vaccines

Vaccination prevents 3.5 to 5 million deaths annually from infectious diseases. But the sudden emergence of the coronavirus disease, the fast rollout of vaccines, compulsory government vaccination regulations, and huge profit margins of vaccine manufacturers contributed to vaccine hesitancy and conspiracy theories about the COVID-19 vaccines. This hesitancy was fueled by a lack of information about vaccine contents and production processes. We show that vaccines are neither a recent idea, nor an offshoot of the COVID-19 pandemic, and we show the constituents of traditional vaccines and COVID-19 vaccines. Vaccine classes include live attenuated vaccines, whole inactivated vaccines, toxoid vaccines, subunit vaccines, recombinant vector vaccines (RVVs), and nucleic acid vaccines (NAVs). COVID-19 vaccines approved for emergency use by WHO are mostly RVVs and NAVs. They have similar ingredients and mechanisms of action to traditional vaccines. Approval of vaccines goes through rigorous phases of research and development, clinical trials, tests by regulatory authorities, and continuous improvement. Production workflow follows generating, releasing, isolating, and purifying the antigen, adding other ingredients before packaging and storage. Some challenges of vaccination are injection pain, negative beliefs, vaccine side effects, and microbial complexities. Compared to other chemotherapeutics, vaccines hold the highest potential in preventing and eradicating infectious diseases.