Counting on COVID-19 vaccine: Insights into the current strategies, progress and future challenges

Abstract

Emergence of a novel coronavirus viz., severe acute respiratory syndrome coronavirus (SARS-CoV-2) in late 2019 and its subsequent substantial spread, produced coronavirus disease 2019 (COVID-19) pandemic worldwide. Given its unprecedented infectivity and pathogenicity, COVID-19 pandemic had a devastating impact on human health and its clinical management. It led to development and speedy trials of several vaccine candidates against SARS-CoV-2 at an exceptional pace; as a result, several COVID-19 vaccines were made commercially available in the 2021 first half. Although, several COVID-19 vaccines showed promising results, crucial in-sights into their epidemiology, protective mechanism and propensity of reinfection are not largely reviewed. In the present report, we provided insights into the prospects of vaccination against COVID-19 and assessed diverse vaccination strategies including DNA, mRNA, protein subunits, vector-based, live attenuated, and inactivated whole/viral particle-based vaccines, imi-tating COVID-19 infection. Next, we reviewed major aspects of various available vaccines ap-proved by the WHO and by local administration to use against COVID-19. Moreover, we com-prehensively assessed the success of these approved vaccines and also their untoward effects in-cluding the possibility of reinfection. We also provided an update on the vaccines that are under development and could be the promising candidate. Conclusively, we provided insights into the COVID-19 vaccine epidemiology, their potency and propensity for SARS-CoV-2 reinfection, while a careful review of their current status, strategies, success and future challenges was also presented.

Immunization with a Prefusion SARS-CoV-2 Spike Protein Vaccine (RBMRNA-176) Protects against Viral Challenge in Mice and Nonhuman Primates

“…Since December 2020, several mRNA vaccines encoding the SARS-CoV-2 S protein have been validated for use by the WHO, including BNT162b2 (Pfizer), mRNA-1273 (Moderna), and NVX-CoV2373 (Novavax). There are also several mRNA vaccine candidates encoding full-length S protein or the RBD under phase I/II/III clinical trials, such as CVnCoV, ARCoV, and BNT162 [14].…”

Cold-adapted SARS-CoV-2 variants with different temperature sensitivity exhibit an attenuated phenotype and confer protective immunity

“…The COVID-19 pandemic has become the main medical challenge of the 21st century. Almost all vaccines for the specific prevention of COVID-19 that have been or are being evaluated in clinical trials are based on replication-defective viral vectors, self-replicating RNA molecules, recombinant or native viral antigen preparations [1] , [2] , [3] , [4] . These technological platforms allow the rapid development of safe vaccines capable of inducing a protective immune response.…”