There are three core stages of testing that potential vaccines undergo before application to the FDA for approval. In the first phase, the vaccine is delivered to a small sample of people,, and its effect on the immune system is measured. This process is repeated with a larger number of people (hundreds) in phase 2. The process in phase 3 is slightly different. The vaccine is administered to thousands of people, with thousands of others receiving a placebo instead. The vaccine is delivered in two injections, at least 4 weeks apart. Then, sufficient time must be allowed for participants to become sick with Covid-19 and so to measure the vaccine’s ability to defend against the virus. This time is also necessary to identify side effects that might not have appeared during the other, shorter trials. A number of companies, such as Sinovac, Sinopharm, CanSinoBio, as well as the Russian Ministry of Health have been allowed to administer their vaccines in certain countries before the results and in some cases, before the beginning of phase three trials.
Among the other vaccines currently in phase three trials are Moderna, Pfizer, Johnson & Johnson, AstraZeneca, NovaVax Bharat Biotech, and Murdoch Children’s Research Institute. In this article I highlight the progress of Moderna, AstraZeneca and NovaVax.
Moderna:
As of this Thursday, Moderna has enrolled 30,000 participants in their phase 3 trials. The vaccine is reportedly now on track to apply to the FDA for authorization to be put into circulation in early December, provided “all the stars align”, as their company president says. Three things need to happen before Moderna applies to the FDA for approval.
53 of the 30,000 participants need to contract Covid-19, of these 53, at least 40 need to be participants who were given the placebo shot of saline to show that the vaccine is at least 75% effective, and 8 weeks must pass after participants were given their second injection so any side effects of the vaccine can be assessed. The company is in hopes that this will happen by late November. As of Thursday 22 October, 26,650 participants had received their second dose of the vaccine/placebo.
AstraZeneca and University of Oxford:
AstaZeneca’s phase three trials started on the 31st of August. This vaccine is also being tested on 30,000 subjects, and again the two doses are administered four weeks apart. The trial was paused for three days between the 9th and 12th of September as a result of an otherwise healthy woman being diagnosed with transverse myelitis (A neurological disorder that causes inflammation on both sides of one section of the spinal cord. It can be caused by infection or immune system disorders). The trial is was given permission to continue its phase 3 trial on Friday the 23rd of October, and company CEO Pascal Soriot still expects to be able to determine the efficacy and safety of the vaccine by the end of the year, with the goal of the vaccine being 50% effective.
NovaVax:
NovaVax is currently in phase three trials in the UK, with 10,000 participants. The company expects to be able to produce 167 million doses of the vaccine, and a production rate of 2 billion doses per year by the middle of 2021, through a deal made with the Serum Institute of India. Again, this vaccine requires two doses to be administered.
The development of a vaccine is a long, frustrating process. All of the companies named in this article had successful, hope inspiring phase 1 & 2 trials. Yet many of them along with many others have not been able to sustain their momentum and have had to pause or delay their final trials.
Despite this, the number of vaccines currently in phase 3 trials, and the number of companies that have claimed their vaccine will be ready for use by the middle of 2021 is extremely encouraging.
However it must be asked who will get there first?
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