The World Health Organization (WHO) recently published a blueprint document that listed 70 vaccine candidates that were leading the way towards a solution to the coronavirus pandemic.

While 67 of those vaccines are still in a pre-clinical phase, three of the vaccines are taking the lead and have now been moved on to clinical trials.

Who is leading the race?

The three developers are:

READ MORE: The new coronavirus: The urgent, but long race for a vaccine 

What are the vaccinations?

1. An adenovirus type 5 vector vaccine

This vaccine by CanSino Biological Inc. and the Beijing Institute of Technology is currently in stage two of clinical evaluation. The vaccine is based on the same platform as the Ebola virus. Adenoviruses are often used as vectors for numerous infectious agents.

2. A DNA plasmid vaccine delivered by electroporation device

The vaccine developed by Inovio Pharmaceuticals is based on the same platform as Lassa, Nipah, Filovirus, HPV, Zika and Hepatitis B. A DNA plasmid vaccine is a vaccine where genetically engineered plasmid containing a DNA sequence that decodes the specific antigen against a virus is injected.

Electroporation is a method to deliver DNA to cells via an electric pulse. The vaccine is currently in stage one of clinical evaluation.

3.  An LNP-encapsulated mRNA vaccine 

This vaccine candidate by Moderna/NIAID and is designed to fight an RNA virus such as SARS-CoV-2. The mRNA sequence in the vaccine is coded to a disease specific antigen, which is recognised by the immune system, which then prepares to fight the virus.

LNP stands for “lipid nanoparticles” which encapsulates the RNA strand injected.

What exactly is a clinical trial?

When a medication or vaccine goes to clinical trial, it has been through the necessary laboratory and animal tests. Where it may normally take years, many companies are fast-tracking the processes to speed up the fight against Covid-19.

The clinical trial is the research trial performed in humans to ensure the safety and efficacy of the vaccine at hand. A clinical trial is used to establish any possible side-effect that a vaccine may cause. A clinical trial usually consists of four phases:

  • Phase 1: An experimental phase with a small group of healthy people, usually between 20 and 80. This phase is usually focused around safety.
  • Phase 2: Where Phase 1 solely focuses on safety, the trial moves on into Phase 2 as soon as safety is established in the small group of people. Now the vaccine is tested in a larger group of people, usually between 100 and 300, to test how effective it is.
  • Phase 3: During this phase, the trial is extended to various groups and populations to determine both safety and efficacy in a diverse group of people.
  • Phase 4: This trial takes place after the use of the vaccine is approved (by a regulatory body such as the FDA, for example). Here, the safety and efficacy are carefully monitored in a large, diverse group of people.

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READ | The new coronavirus: The urgent, but long race for a vaccine

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