How long will it take to get the Oxford vaccine to deployment?
Vaccine development during an epidemic
Experts have estimated that it will take 12-18 months to develop a new vaccine at high speed. Under normal circumstances, most vaccine development programmes take more than five years, so this is still a considerably accelerated timescale.
This 12-18-month prediction includes the time taken to develop manufacturing processes to produce the vaccine on a larger scale, as well as preclinical testing in animals and evaluation of the vaccine in human participants in a clinical trial. Scientists need to assess the safety and efficacy of the vaccine over a number of weeks and months through phase I, II and III clinical trials. If the vaccine is safe and efficacious, regulatory approval is needed before the vaccine can be deployed.
Many of these stages can be undertaken more quickly if there are no unexpected roadblocks. Firstly, the use of a platform technology approach, i.e. a vaccine delivery system that has been used before and can be adapted for a new pathogen, can shorten the initial vaccine development time. Also, in an emergency situation, large scale manufacturing could be carried out concurrently while the clinical trial is ongoing, which can shorten the overall timescale for vaccine development. This would mean that if the clinical trial is successful, the vaccine would be ready in larger quantities, to be deployed immediately. Finally, regulatory review of promising candidates is also undertaken faster in an epidemic, because more staff and resources are dedicated to the review process.
Oxford University is using all these strategies in order to try to make a vaccine available as rapidly as possible once it is proven safe and effective.
The ChAdOx1 nCoV-19 vaccine timeline
We must remain cautious when mapping out a timeline for the trial. The plans for the clinical trial are as follows:
||Vaccinate 510 volunteers aged between 18-55, half with the new COVID-19 vaccine and half with a control vaccine.
||Extend the maximum age of trial participants to 55-70 years, then over 70.
Vaccinate 5000 volunteers aged over 18 years, half to receive the COVID-19 vaccine. Clear efficacy endpoints will be used to assess the effectiveness of the vaccine, and volunteers from phase I and II will be included in the follow-up.
The best-case scenario is that by the autumn of 2020 we could have an efficacy result from the phase III trial to show that the vaccine protects against the virus, alongside the ability to manufacture large amounts of the vaccine, but these best-case timeframes are highly ambitious and subject to change.
Our ability to determine vaccine efficacy will be affected by the amount of virus transmission in the local population over the summer, and we are also beginning to consider initiating trials with partners in other countries to increase our ability to determine vaccine efficacy.
Author: Dr Tonia Thomas, Oxford Vaccine Group