Safety and Considerations of the COVID-19 Vaccine Massive Deployment

Abstract

Emerging and re-emerging infectious diseases represent a significant and growing cause of morbidity and mortality. Since vaccination campaigns were carried out, several infectious diseases have been controlled successfully, such as smallpox and poliomyelitis, making vaccination one of the most reliable and cost-effective public health interventions. In the long run, vaccine coverage, whether high or low, has been shown to yield important public health benefits (Weycker et al. 2005). Therefore, vaccines play an important role in increasing population immunity, preventing severe infectious diseases, and reducing the ongoing public health crisis. Due to herd immunity and consequent herd protection induced by vaccines, deployment of mass vaccination is vital to prevent and control the transmission of the emerging infectious diseases directly or indirectly. In early 2020, the coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread rapidly worldwide, developing into a global COVID-19 disease pandemic. Hitherto, it has resulted in more than hundred millions of infections and three million deaths. Such a grave situation has made the development of a safe and effective COVID-19 vaccine imperative and urgent as a primary tool to prevent and eventually contain the spread of SARS-CoV-2. However, developing, scaling-up mass production, approval and distribution of COVID-19 vaccines rapidly in this global pandemic setting is challenging as it requires many activities, sequential process with pre-clinical testing, phased clinical trials, planned production, evaluation and followingup surveillance and facesmuch uncertainty. Being surprised, in this competition between spread and containment of SARS-CoV-2, groundbreaking universal effort in the development of vaccines against SARS-CoV-2 has shown great success unparalleled in the history of human vaccine development with an unprecedented pace thus far. Since the announcement of the genetic sequence of SARS-CoV-2 on January 12, 2020, it took only twomonths to the start of phase I clinical trial of candidate vaccines. On March 16, 2020, vaccine mRNA-1273, which encodes the spike protein (S protein) of SARS-CoV-2, developed by Moderna and the Vaccine Research Center (VRC) of the National Institute of Allergy and Infectious Diseases (NIAID), entered phase I clinical trial. On the same day, a non-replicating adenovirus type 5 vector of COVID-19 vaccine was announced to enter phase I clinical trial conducted by CanSino Biological Inc./ Beijing Institute of Biotechnology. Currently, more than one hundred of COVID-19 vaccines are under ongoing doubleblinded, randomized, and controlled clinical evaluation. Some of these have shown good safety and immunogenicity, and among them, more than 60 of these are being evaluated in phase III clinical efficacy studies globally. Recently, integrated analysis of phase I, II, and III trials of COVID-19 vaccines was published one after another. These results showed that most COVID-19 vaccines provided protection among the vaccinated participants (Polack et al. 2020; Voysey et al. 2020). Based on the promising clinical data of COVID-19 vaccines, the United Kingdom (UK) has given approval first for use of COVID-19 vaccine, BNT162b2, by following a thorough review carried out by the Medicines and Healthcare products Regulatory Agency (MHRA) on December 1, 2020. Another mRNA vaccine, mRNA-1273, was authorized by the Food and Drug Administration (FDA) that issued an emergency use authorization (EUA) for general vaccination among health & Yongxiang Yi [email protected]