COVID-19 vaccine: where are we now and where should we go?

Abstract

Introduction The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has currently caused the pandemic with a high progressive speed and has been considered as the global public health crisis in 2020. This new member of the coronavirus family has created a potentially fatal disease, called coronavirus disease-2019 (COVID-19). Despite the continuous efforts of researchers to find effective vaccines and drugs for COVID-19, there is still no success in this matter. Areas covered Here, the literature regarding the COVID-19 vaccine candidates currently in the clinical trials, as well as main candidates in pre-clinical stages for development and research, were reviewed. These candidates have been developed under five different major platforms, including live-attenuated vaccine, mRNA-based vaccine, DNA vaccines, inactivated virus, and viral-vector-based vaccine. Expert opinion There are several limitations in the field of the rapid vaccine development against SARS-CoV-2, and other members of the coronavirus family such as SARS-CoV and MERS-CoV. The key challenges of designing an effective vaccine within a short time include finding the virulence ability of an emerging virus and potential antigen, choosing suitable experimental models and efficient route of administration, the immune-response study, designing the clinical trials, and determining the safety, as well as efficacy.

Fine needle aspiration in COVID-19 vaccine-associated lymphadenopathy

“…Various vaccines are being evaluated, with currently 322 vaccine candidates and 18 in use worldwide [7][8][9][10]. So far, three have been approved in Switzerland (Comirnaty ® by Pfizer-BioNTech on 19 December 2020, COVID-19 Vaccine Moderna ® by Moderna on 12 January 2021 and COVID-19 Vaccine Janssen by Johnson&Johnson on 22 March 2021).…”

An Updated Review of SARS-CoV-2 Vaccines and the Importance of Effective Vaccination Programs in Pandemic Times

“…Vaccination is playing a central role in the SARS-CoV-2 pandemic, impeding new infections, while saving millions of lives. However, there is no denying the fact that it is only the starting point and there are still many issues to address, such as unraveling the virulence ability of SARS-CoV-2 and choosing suitable experimental models and designs for clinical trials, and more robust scientific evidence is needed to fully evaluate the safety and efficacy of COVID-19 vaccines [ 96 ]. Additionally, the global economy has greatly suffered during this pandemic, and vaccines should also aim to achieve their maximum benefits with the minimum dose, such as Johnson and Johnson’s vaccine.…”

“…By contrast, the other vaccines in clinical development are viral-vector-based (AstraZeneca + Oxford and the more recent Janssen Pharmaceutical vaccine) and, more recently, inactivated-virus-based (Sinovac), but these have also shown promising results. The success of those vaccines that advanced more quickly through clinical trials was largely due to well-designed routes of administration and immune-response studies [ 96 ].…”

“…The mechanism is triggered similarly as in the previous cases highlighted above. Monocyte activation promotes IFN expression, and this activates CD4+ T cells, boosting antibody secretion by B cell activation, along with CD8+ cells, promoting the killing of infected cells [ 96 ]. CoronaVac elicited 92.4% seroconversion in participants after two weeks and 97.4% after 4 weeks with second administration [ 149 ].…”

Healthcare workers' Attitude and Knowledge Towards the Safety of Nucleotide-Based Vaccines.

“…In assessing the knowledge and attitude of healthcare workers, students, and researchers on their preferred type of NBVs, the analysis revealed the population to view RNA-based NBVs as a safer option as compared to DNA based ones as a whole (Table 2), which perhaps reveals an issue of skepticism towards the safety of DNA therapy as a whole. (Park et al 2021) (Soleimanpour and Yaghoubi 2021) Giving a brief educational material about NBVs yielded no difference when challenged by questions not solidly based on scienti c theory (RNA being more readily degraded than DNA, or DNA producing foreign proteins only), which indicates a healthy scienti c base among Jordans' healthcare workers regarding this topic (Table 2). On the other hand, the educational material proved signi cant in altering the participants' views on NBVs safety in favor of the RNA-based NBVs as opposed to DNA-based NBVs due to the reduced risk of genome incorporation (gene editing) (Pacheco et al 2021), a very common theme in the controversy surrounding NBVs.…”