One question is in everyone’s mind: when will a vaccine against SARS-CoV-2 be available? Unfortunately, there is no easy answer. The development of vaccine is a long and complex process.
Here is the brief explanation why it talks so long. To come up with a vaccine, traditionally, every institution needs to follow the following steps and each step requires many months and years. Briefly they are: (1) exploratory stage: basic research, a strategy on how to construct the vaccine, may take 2–4 years; (2) pre-clinical stage: whether vaccine candidate can produce significant immunity in mammalian cells grown in laboratory or in laboratory animals; (3) investigational new drug application: If the pre-clinical stage is successful, then companies or designated institutes submit applications for an investigational new drug to the US Food and Drug Administration and start phase 1 vaccine trial; (4) Phase I vaccine trials: for Phase I vaccine trials, they first try in a small number usually 45–100 of adults (in the age group of 25–60 years) people by notifying them. The goals of Phase 1 testing are to assess the safety of the candidate vaccine and to determine the type and extent of immune response that the vaccine provokes; (5) Phase II vaccine trials: in this trial, they recruit a larger group of people, usually several hundred, and expand the age group up to 70. This phase done in a randomised fashion means a half will be given the real vaccine and the remaining half will get similar product without vaccine. The goals of Phase II testing are to study the candidate vaccine’s safety, immunogenicity, proposed doses, the schedule of immunisations and the method of delivery. Successful Phase II candidate vaccines move on to Phase III trials; (6) Phase III trials: this phase involves thousands to tens of thousands of people. If everything goes as per the plan, the companies apply for an approval and licence for marketing; (7) In Phase IV trials, some companies collect data on safety and efficacy even after marketing the products for a few years and make sure that the intended goal is achieved. For SARS-CoV-2, the steps may be shortened using enormous work force in an expeditious manner.
For the reasons, usually a vaccine takes 10–14 years. More than 100 known institutions and companies are now working relentlessly to come up with one, using different approaches. In my scientific career, I have never seen more than 200 diagnostic products being available for a single virus diagnosis and neither have I seen more than 100 companies tightening their belts to come up with a vaccine in 12–18 months. Since April, almost 80 of them were in preclinical evaluation, according to the World Health Organisation. China, the United States, Germany and the United Kingdom are ahead in the game and all of them have moved on to clinical trials with human subjects.
CanSinoBio, a Hong Kong-based biotech firm backed by the Academy of Military Medical Sciences along with the Beijing Institute of Biotechnology developed a vaccine. They got approval for use of the candidate in humans on Match 13. The vaccine, known as Ad5-nCoV, is an adenovirus Type 5 vector-based vaccine already in Phase II development in Wuhan, China. CanSinoBIO and the National Research Council, Canada have had a relationship since 2013 and the Ad5-nCoV vaccine was developed using cell lines developed at the National Research Council, a federal research and development organisation headquartered in Ottawa. Very recently, the Canadian government gave green signal to Phase 1 trial of the vaccine in Canada and the trials have been approved by Health Canada and will take place at the Canadian Centre for Vaccinology at Dalhousie University in Halifax. They hope to get this vaccine out by September for an emergency use even before Phase III is completed. If all goes well, this vaccine will also be produced in Canada as well.
Moderna/National Institute of Allergy and Infectious Diseases is on the front line as well. Moderna’s vaccine uses a different mechanism, being a messenger RNA-based vaccine rather than using adenoviral vectors. Vaccines using this technology have never been used in humans in the past. It announced on March 16 that it had given the potential vaccine to the first person in clinical trials. The first phase of the trial aimed at enrolling 45 healthy volunteers aged between 18 and 55 years and was expected to take approximately six weeks. The vaccine is designed by using the sequence of the virus, which was shared globally by Chinese authorities in early January. It announced recently that it was expanding to add older adults and elderly adults as volunteers for Phase I testing. It has done Phase I and found virus-neutralising antibodies similar to what is found in recovered patients which is very promising; the only side affect found is redness on the injection site. Moderna will start Phase II soon and hopes to get permission to vaccinate people in July under an emergency situation for high-risk individuals. Everything is moving at fast pace.
Oxford University’s Jenner Institute started Phase I clinical human trials of a candidate called ChAdOx1 nCoV-19 a few weeks ago. ChAdOx1 nCoV-19 is made of a genetically modified common cold virus (ChAdOx1), used to cause infection in chimpanzees, but because of genetic manipulation by adding COVID-19 protein, it is impossible for it to grow this virus in humans and to produce immune response against SARS-CoV-2. The first phase clinical trials involve 510 volunteers between aged between 18 and 55 years. This group has a very ambitious goal. The Oxford Jenner Institute has already agreement with AstraZeneca, a giant biotech company that will mass-produce this vaccine and distribute globally but, of course, British people will get access first. Researchers at the Jenner Institute and the Oxford Vaccine Group would know whether their candidate vaccine would be able to effectively prevent COVID-19 infections. They also hope that this vaccine will be available by September 2020.
Another American company, INOVIO Pharmaceuticals, started trial of its candidate named INO-4800 with 40 healthy volunteers in Philadelphia and Kansas City and plans to expand it to more than 2,000 patients. INOVIO will use its proprietary DNA plasmid-based product that is a new method and a completely different approach compare with traditional vaccine-making process. It seems to be working well for other microorganisms although it is in different stages of clinical trials.
The Biopharmaceutical New Technologies, a German company, collaborating with Pfizer in the United States also completed a potential candidate called BNT 162 in Germany in the last week of April. It is using a molecular based technology over egg-based traditional vaccine. Its clinical trial will be escalated to another 200 healthy volunteers aged between 18 and 55 years.
Now all the front-runners are competing with one other. Some promising vaccine will be ready by 2021 and some of them by the end of 2020 and a few of them even say that vaccines will be available by September 2020 for an emergency use. It takes long time to bring a vaccine to the market because many steps will be shortened or Phase and I and II will be combined together, recruiting more patients, etc.
I think the way vaccine companies are racing to provide a product for human consumption to combat this monstrous virus, we may see a vaccine or few vaccines within less than a year or so. But the million-dollar question is: would we be able to see a safe, effective and long-lasting vaccine against SARS-CoV-2?
Dr Muhammad Morshed is a clinical microbiologist and programme head, zoonotic diseases and emerging pathogens, at BC Centre for Disease Control and clinical professor, department of pathology and laboratory medicine, University of British Columbia.
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