Vaccines Versus Covid-19 Vaccines: Maneuver Timeline of Development and Trial Designs

Abstract

Recent pandemic of coronavirus disease 2019 (COVID-19) has made a serious threat to public health and became a global burden with millions of people at risk of death. At that time, there were no approved antiviral drugs and vaccines for COVID-19, but few drugs are repurposed with limited benefit. In less than a year, several COVID-19 vaccines have already been approved and hundreds of vaccines are undergoing clinical evaluation. This review focuses on need for vaccines, benefits of vaccination, the World Health Organization initiated new global strategy ‘the Immunization Agenda 2030’ (IA2030), stages and timeline of development, and clinical evaluation of traditional vaccines. We have summarized comparison of clinical evaluation between traditional vaccines and conventional drugs in the pre-pandemic era. The review briefly discusses the prioritized approaches, accelerated timeline of clinical evaluation, and seamless and immunobridging clinical trial designs of COVID-19 vaccines in the pandemic period. We have thoroughly searched recent literature and data on this topic and made a summary of current advances, regulatory amendments, and future perspectives of development and approval of vaccines.

The World of Vaccines: Phases of Clinical Trials and Current Status of COVID-19 Vaccines

“…7 Moreover, "The Immunization Agenda 2030" (IA2030) of the WHO has been initiated to achieve 90% coverage for essential vaccines in children and adolescents, to reduce the rate of vaccine missing out by 50%, and the clinical development and approval of 500 novel vaccines in the low and middle-income countries (LMICs) for the next ten years. 8,9 In line with this, 17 and 25 vaccines are introduced in 2020 and 2021, respectively. These new vaccine approvals and introductions are not limited to dengue, malaria, Ebola virus disease, and respiratory syncytial virus but future introductions might be extended to several vaccine candidates against influenza and tuberculosis as well as neutralizing antibodies and therapeutic vaccines for Alzheimer"s disease and cancer.…”

“…These new vaccine approvals and introductions are not limited to dengue, malaria, Ebola virus disease, and respiratory syncytial virus but future introductions might be extended to several vaccine candidates against influenza and tuberculosis as well as neutralizing antibodies and therapeutic vaccines for Alzheimer"s disease and cancer. [9][10][11] In late 2020, the entire world was eagerly waiting for an effective vaccine that has been developed and clinically evaluated by scientifically proven and validated methodologies to be approved. This unprecedented time realized people the facts that hygiene approaches of wearing masks, applying hand sanitizers, and social distancing were only temporarily avoiding spread of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and only a vaccine might protect and end the lockdown.…”

“…This unprecedented time realized people the facts that hygiene approaches of wearing masks, applying hand sanitizers, and social distancing were only temporarily avoiding spread of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and only a vaccine might protect and end the lockdown. 9,12 Prospectively, the COVID-19 pandemic is a great and unique example of how vaccines, vaccinations, and immunizations are really gamechangers that can improve lives across the world.…”

“…However, preclinical and clinical evaluation is prototypical for the assessment of the safety, efficacy, and effectiveness of vaccines. 8,9,12 A typical timeline of a standard vaccine development takes 5 to 15 years due to extensive clinical evaluation, delays in regulatory approval processes, and time for bulk manufacture and distribution. 9,[13][14][15] The typical development of a vaccine occurs in six stages, viz.…”

“…8,9,12 A typical timeline of a standard vaccine development takes 5 to 15 years due to extensive clinical evaluation, delays in regulatory approval processes, and time for bulk manufacture and distribution. 9,[13][14][15] The typical development of a vaccine occurs in six stages, viz. (1) Exploratory/Discovery stage, (2) Preclinical stage, (3) Clinical development stage (Phases 1-3), (4) Regulatory review, licensure, and approval stage, (5) Manufacturing stage, and (6) Post-licensure stage (Phase 4).…”