It has been more than six months since CoVID-19 became an urgent threat in the United States. It’s been eight months since the virus was first identified in Wuhan, China.
Today, everyone is waiting to learn when an effective COVID-19 vaccine will arrive. Hundreds of potential COVID-19 vaccines are under development globally, and they have been for months.
The purpose of this article to identify and explain the phases of vaccine trials and why they take so long. It’s also to provide a progress report on the trials currently in process.
The Typical Vaccine Development Timeline and Associated Terms
Historically, it has taken five to ten years for a vaccine to be developed and reach doctor’s offices. The many doctors, scientists, and others involved in the COVID-19 process are trying to speed this up.
However, the timeline for developing and testing a vaccine takes much longer than most people realize. Allow us to explain.
The U.S. Food and Drug Administration (FDA) uses “phases” to label the progress of a drug or vaccine’s clinical trial. This is based on the study’s characteristics, such as the goal and number of participants. The five phases are as follow.
This is the preliminary phase, at which vaccines are still being tested in labs. They have not yet begun to be tested on humans.
Here, a few people test an experimental vaccine. They assess its safety, identify possible side effects, and determine safe dosages.
During this phase, larger groups of people are enlisted to assess whether an experimental vaccine works effectively and is safe. This phase might last several years.
Here, the trials tend to be expansive studies comparing the experimental vaccine to a placebo or standard treatment. At this stage researchers determines whether the drug works and then collect information to ensure its safe use.
Phase IV (approval)
At this final stage, a vaccine has reached the market, and trials are used to provide additional information about its best applications.
Of course, the FDA phases are only one set of national guidelines among many. Still, members of the global medical and scientific communities conducting vaccine research follow each other’s progress diligently and uphold similar protocols.
The COVID-19 Vaccine Timeline
On August 5, 2020, the New York Times reported the following data about which vaccine-development entities are in each trial phase:
- Preclinical: 140+
- Phase I: 18
- Phase II: 12
- Phase III: 6
- Phase IV: 1
We hope these numbers help you appreciate how much research and experimentation must occur before a vaccine trial is approved for human testing, and how much winnowing happens as it moves through the phases.
What about that one vaccine that has reached the final stage? What of those that have made it to Phase III? Let’s find out.
Progress of the COVID-19 Vaccine Development as of August 2020
The vaccines in various trial phases fall into different categories. In this section, we summarize the progress in each category. You will note that most of the vaccines discussed are in multiple stages to speed up the approval process.
Genetic vaccines, also known as DNA vaccines (or immunizations), are meant to stimulate an immune response to protein antigens (antibody producers).
Injecting genetic material into a human host causes a small number of its cells to produce the introduced genes. This can result in the host’s immune system reacting against the gene-delivered antigens.
Some genetic vaccine trials that have reached Phase III include:
- Moderna in partnership with the National Institutes of Health
- Germany’s BioNTech in partnership with China’s Fossun Pharma
Viral Vector Vaccines
Like genetic vaccines, viral vector vaccines use one or more of a virus’s original genes to provoke an immune response. However, with these, the genetic material shuttled by the virus (vector) has been altered, enabling an immune response by the host’s body.
Some viral vector vaccine trials that have reached Phase III include:
- AstraZeneca in partnership with the University of Oxford
Protein-based vaccines involve harvesting plasma from recovered virus victims. Any remaining virus is neutralized, and the antigens are processed and made into a vaccine. In other words, the vaccines use antigens to fight off viral infections.
There currently are no Phase III trials for protein-based vaccines.
Whole-virus vaccines use an attenuated (weakened or inactivated) version of a virus to provoke an immune response. Classic examples of these include the vaccines for measles and chickenpox.
Some whole-virus vaccine trials that have reached Phase III include:
- China’s Wuhan Institute of Biological Products
- China’s Sinovac
Repurposed vaccines use existing vaccines for other diseases. The hope is that they will also protect against the virus needing treatment, in this case, COVID-19.
The goal here is for the immune system to “remember” the disease being used in the vaccine and develop immunity.
One genetic vaccine trial using the tuberculosis virus has reached Phase III. It is Australia’s Murdoch Children’s Research Institute.
The One Vaccine That Is in Phase IV
The Chinese company CanSino Biologics developed a vaccine based on an adenovirus (common cold virus) called Ad5. This was in partnership with the Institute of Biology at China’s Academy of Military Medical Sciences.
The partners published promising results from May Phase I safety trials. Then, in July, they announced that those trials had shown that the vaccine led to “a strong immune response in the test subjects.”
Remarkably, the Chinese military approved the vaccine on June 25 for a year as a “specially needed drug.”
What Will the Future Hold for a COVID-19 Vaccine?
It seems clear from what we discussed here that a great deal of progress has been made toward a COVID-19 vaccine within a very short time.
If this pace continues, it seems we’re likely to see other companies, institutions, and teams reach the approval stage soon. You should be aware, though, that not all approved vaccines will be available to everyone at the same time.
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Coronavirus Vaccine Tracker
https://www.nytimes.com/interactive/2020/science/coronavirus-vaccine-tracker.html (accessed Aug. 5, 2020)
Glossary of Clinical Trial Terms (Novartis)
The History of Vaccines
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