Many experts say a return to normalcy is impossible without a vaccine. How close are we? Let’s look at the process.
The current COVID-19 pandemic affects all of us in both direct and indirect ways. When will distancing guidelines and travel restrictions be eased? Vaccine development efforts are well underway but any such drug must be both safe and effective.
Where do things stand? First, it may be helpful to understand how these therapies are designed and developed. Let’s discuss the drug development process to discover how close we may be to a COVID-19 vaccine.
1. Know Your Mission
What Is the COVID-19 Vaccine?
A COVID-19 vaccine will trigger our immune system to produce antibodies that will protect us when exposed to the virus. In this way, it will prevent COVID-19 from spreading within our bodies and protect those around us.
A successful COVID-19 vaccine must be efficient, effective, and safe.
Where Do We Start?
First, we must understand the structure of COVID-19 virus.
Structures that trigger our immune system are known as antigenic structures. To design an effective vaccine, you need to select the most appropriate antigenic structures, which can be determined by conducting exploratory studies or through a review of the scientific literature.
The video below highlights COVID-19 structures.
Reported Antigenic COVID-19 Structures
Researchers have identified several COVID-19 structures capable of triggering our immune system. They include:
- Spike glycoprotein (S)
- Nucleocapsid protein (N)
- Non-structural proteins (nsp3, nsp8)
- Nucleic acid (RNA)
You can return to the video to view them.
We Have Our Target, What’s Next?
As part of this step, scientists decide on the most suitable way to deliver the vaccine. The available methods include:
- Introducing the complete viral structures after attenuating or inactivating it. This gives you a live-attenuated or inactivated vaccine.
- Introducing a specific viral structure, making a subunit, or recombinant vaccine.
- Introducing the specific part of viral protein that triggers our immune system “peptide”. This gives you a peptide-based vaccine.
From here, we design our probable “candidate” vaccine.
2. We’ve Designed Our Candidate Vaccine, Now What?
At this point, we need to prove that our candidate vaccine will protect us.
This means conducting experimental studies to gather sufficient evidence. Specifically, we’ll study the ability of our candidate vaccine to:
- Trigger our immune system (efficacy)
- Not harm us through side effects (safety)
How Can We Prove That Our COVID-19 Vaccine Is Successful?
As mentioned previously, you must conduct experimental studies for your candidate vaccine.
Before we can begin studying the effects of the vaccine in humans, we must test the safety and efficacy of it in experimental animals. The studies include:
- Tests in experimental animals (pre-clinical trials)
- Tests in humans (clinical trials)
Before you start your animal testing, you need a “clearance” from your institution’s ethics committee.
Next, you’ll select suitable experimental animals like rats and monkeys. Then, you give them your candidate vaccine. You’ll see if they form enough COVID-19 antibodies and observe the side effects.
The pre-clinical studies help you determine safety, efficacy, and toxicity issues, as well as identify approximate dose levels.
Once you achieve reasonable results, you can proceed to the next step.
Since clinical trials involve humans, you need “informed consent” from the participants. Also, you need approval from regulatory agencies, including the U. S Food and Drug Administration (FDA) and the European Medicines Agency (EMA).
Clinical trials include four stages, or phases. I’ve summarized them for you below.
|Phase 1||a small group of healthy volunteers (up to 100)||To assess the safety, efficacy, and the preliminary dose level|
|Phase 2||different populations (up to 1000)||To get more information about the efficacy and safety, and to know the largest safe dose|
|Phase 3||larger populations including control group (several thousand)||To get clear information about safety, efficacy, and side effects at the optimal dose|
|Phase 4||Whole market||Track your licensed vaccine in the market. To ensure its efficiency and record its long-term side effects if appeared|
After you complete Phase 3, you can apply for a “biological license.” If the regulatory organization approves your application, you’ll have the right to license, manufacture, and market your vaccine.
3. What Else Should I Know?
Before Entering the Market
Since your target is the entire world population, you need to extend your production line. This will allow you to make enough doses to cover everyone.
Estimated Time to Get a Successful COVID-19 Vaccine?
You may notice that the journey to a successful COVID-19 vaccine involves many steps. You’d do them rigorously to ensure safety and efficacy.
On a normal track, it may take up to 15 years to deliver a vaccine. But, given the urgent nature in this case, a fast-track strategy is allowed, shortening the timeline to 12-18 months.
Current COVID-19 Vaccines Under Development
There are more than 100 candidate vaccines under development. They encompass:
- 137 candidates in the pre-clinical stages
- 23 candidates in the early stages of clinical trials
In the table below, I have listed those in Phase 3 clinical trials.
|Name||Type||Developer||Approximate participants number|
|AZD1222||Recombinant vaccine||University of Oxford and AstraZeneca company||30,000|
|Bacillus Calmette-Guerin (BCG)||Live-attenuated vaccine||University of Melbourne, Murdoch Children’s Research Institute, Radboud University Medical Center, Faustman Lab at Massachusetts General Hospital||10,000|
|BNT162||Subunit (modified mRNA)||Pfizer and BioNTech companies||30,000|
|CoronaVac||inactivated vaccine||Sinovac Company||9,000|
|Inactivated vaccine||Inactivated vaccine||Wuhan Institute of Biological Products and China National Pharmaceutical group||15,000|
|mRNA-1273||Subunit vaccine||Moderna biotechnology company, and the U.S National Institute of Health||30,000|
- Employing drug delivery strategies to create safe and effective pharmaceuticals for COVID-19
- COVID-19 Vaccines: A Race Against Time in the Middle of Death and Devastation!
- COVID-19: A Review of Emerging Preventative Vaccines and Treatment Strategies
- SARS-CoV-2 (COVID-19) Vaccine Development and Production: An Ethical Way Forward
- Rapid development and deployment of high‐volume vaccines for pandemic response
- COVID-19 vaccine design: the Janus face of immune enhancement
- World Health Organization DRAFT landscape of COVID-19 candidate vaccines
- The University of Melbourne, SARS lessons for COVID-19 vaccine design
- Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomized controlled trial
- COVID-19 vaccine tracker
- CORONAVIRUS VACCINES
- NIH clinical trial of investigational vaccine for COVID-19 begins
- Ongoing Trails for Bacille Calmette-Guerin (BCG) Vaccines in the prevention of COVID-19
- The COVID-19 Live Vaccine Tracker, Contagion Live Infectious Disease Today