Table 3.

The progress in development of vaccines by different companies and institutes throughout the world [16–20, 90, 91]

Vaccine under trial	Name of the company	Platform	Discussion	Current status
mRNA-1273 [16]	Moderna	RNA	This is a novel lipid nanoparticle (LNP)-encapsulated mRNA-based vaccine that encodes for a full-length, prefusion stabilized spike (S) protein of SARS-CoV-2. The protein S complex is necessary for membrane fusion and infection of host cells. Thus, the stabilized prefusion coronavirus spike protein responsible for Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS) can be used as a vaccine antigen to produce robust neutralizing antibody responses. The vaccine is packed with mRNA. The genetic material originates from DNA and makes proteins. Moderna carries its vaccine with mRNA that encodes the correct coronavirus proteins, which are injected into the body. The immune cells present in the lymph nodes can process this mRNA and start making the protein in the right way for new immune cells to identify it and mark it for damage	Phase-III clinical trial (NCT04470427)
Ad5-nCoV [17]	CanSino Bio and Institute of Biotechnology of the Academy of Military Medical Sciences	Non-Replicating Viral Vector	In China, Ad5-nCoV is the first novel coronavirus vaccine for COVID-19. This is a genetically engineered vaccine candidate with the replication-defective adenovirus type 5 as the vector to express SARS-CoV-2 spike protein. Preclinical animal studies of this vaccine candidate showed that it can persuade a strong immune response in animal models. Preclinical animal safety studies also exhibited a good safety profile	A Phase-III trial in Saudi Arabia is currently underway
AZD1222 (previously called ChAdOx1) [18]	Jenner Institute-University of Oxford	Non-Replicating Viral Vector	This vaccine candidate was developed by Jenner Institute based on a chimp adenovirus vector. For the clinical trials, recruiting 510 healthy volunteers, aged between 18 and 55 years, in a single-blinded, randomized, placebo-controlled, multi-center study to determine efficacy, safety, and immunogenicity of this vaccine	Phase-II/III clinical trial
LV-SMENP-DC [90]	Shenzhen Geno-Immune Medical Institute	Lentiviral	A synthetic minigene has been engineered based on conserved domains of the viral structural proteins and a polyprotein protease. The entry of SARS-CoV-2 is intermediated through attachment of the S protein to the ACE2 receptor and the viral replication depends on molecular mechanisms of all of these viral proteins. In this vaccine, a competent lentiviral vector system (NHP/TYF) was used to convey COVID-19 minigenes to express viral proteins and immune modulatory genes to modify dendritic cells (DCs) and to activate T cells	Phase-I/II clinical trial (NCT04276896)
Bacillus Calmette–Guérin (BCG) Vaccine [19]	Research group, Netherlands	Live Attenuated Virus	The Research group will recruit 1000 healthcare workers in eight Dutch hospitals who will either receive the BCG vaccine, or a placebo	Phase-III clinical trial
BCG Vaccine [20]	Murdoch Children’s Research Institute	Live Attenuated Virus	This is one of the oldest vaccines available in the market. It is made from live, attenuated bovine tuberculosis bacillus, Mycobacterium bovis which induces an adaptive immune response against tuberculosis bacterium. Due to availability in the market, they utilize this vaccine directly in Phase-III clinical trials. This is an open-label, two-group, Phase-III randomized controlled trial in up to 4170 healthcare workers across Australia	Phase-III clinical trial (NCT04327206)
Oral bacTRL-Spike [91]	Symvivo Corporation	Oral vaccine for COVID-19	bacTRL-Spike-1 will be the first-in-human study of bacTRL-Spike, and the first-in-human use of orally delivered bacTRL. It is a genetically modified, probiotic-based oral vaccine for COVID-19. The study design is a phase 1, randomized, observer-blind, placebo-controlled trial in 84 healthy adults [63 receiving active vaccine in bacterial medium and 21 receiving placebo (bacterial medium only)]	Phase-I clinical trial (NCT04334980)