Scientists at Oxford University think they have a SARS-CoV-2 vaccine candidate that can jump ahead of those under development at Johnson & Johnson, Moderna, and dozens of smaller biopharmaceutical companies. The current vaccine development record is four years from discovery to approval, but the Jenner Institute team thinks the candidate it has in clinical trials for the could be ready for the public this fall.
The Oxford team's vaccine, which it has dubbed ChAdOx1 nCoV-19, uses an increasingly popular method to deliver therapeutic DNA sequences: a non-replicating adenovirus. ChAdOx1 nCoV-19 and its predecessor, ChAdOx1 MERS, use the same adenovirus to inject genetic blueprints for the spike proteins that give coronaviruses their characteristic shape.
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Earlier this year, a clinical trial with ChAdOx1 MERS provided some evidence the Oxford team's adenovirus vector was safe and the vaccine appeared arguably effective at preventing transmission of MERS. This allowed the recruitment of 510 volunteers for a clinical trial to begin in March; if initial results are encouraging, that study could grow to more than 6,000 participants by the end of May.
No sick monkeys
A preclinical study with non-human primates recently showed encouraging results. Researchers from the National Institutes of Health inoculated six rhesus macaque monkeys with ChAdOx1 nCoV-19, then exposed them to SARS-CoV-2, the coronavirus that causes COVID-19. After 28 days, all six monkeys were still healthy.
Sadly, the vast majority of new vaccine candidates that look promising during pre-clinical development fizzle out once their efficacy is rigorously tested in humans. While macaques are relatively close genetic relatives to humans, which makes them useful early test subjects for medicines, this sign of efficacy should be viewed as a prerequisite for investing in human clinical trials, and nothing more.
