Coronavirus vaccine: when will it be ready? | World news | The Guardian - 0 views
-
Even at their most effective – and draconian – containment strategies have only slowed the spread of the respiratory disease Covid-19. With the World Health Organization finally declaring a pandemic, all eyes have turned to the prospect of a vaccine, because only a vaccine can prevent people from getting sick.
-
This unprecedented speed is thanks in large part to early Chinese efforts to sequence the genetic material of Sars-CoV-2, the virus that causes Covid-19. China shared that sequence in early January, allowing research groups around the world to grow the live virus and study how it invades human cells and makes people sick.
-
Coronaviruses have caused two other recent epidemics – severe acute respiratory syndrome (Sars) in China in 2002-04, and Middle East respiratory syndrome (Mers), which started in Saudi Arabia in 2012. In both cases, work began on vaccines that were later shelved when the outbreaks were contained. One company, Maryland-based Novavax, has now repurposed those vaccines for Sars-CoV-2, and says it has several candidates ready to enter human trials this spring. Moderna, meanwhile, built on earlier work on the Mers virus conducted at the US National Institute of Allergy and Infectious Diseases in Bethesda, Maryland.
- ...6 more annotations...
-
All vaccines work according to the same basic principle. They present part or all of the pathogen to the human immune system, usually in the form of an injection and at a low dose, to prompt the system to produce antibodies to the pathogen. Antibodies are a kind of immune memory which, having been elicited once, can be quickly mobilised again if the person is exposed to the virus in its natural form.
-
Cepi’s original portfolio of four funded Covid-19 vaccine projects was heavily skewed towards these more innovative technologies, and last week it announced $4.4m (£3.4m) of partnership funding with Novavax and with a University of Oxford vectored vaccine project. “Our experience with vaccine development is that you can’t anticipate where you’re going to stumble,” says Hatchett, meaning that diversity is key. And the stage where any approach is most likely to stumble is clinical or human trials, which, for some of the candidates, are about to get under way.
-
An illustration of that is a vaccine that was produced in the 1960s against respiratory syncytial virus, a common virus that causes cold-like symptoms in children. In clinical trials, this vaccine was found to aggravate those symptoms in infants who went on to catch the virus. A similar effect was observed in animals given an early experimental Sars vaccine. It was later modified to eliminate that problem but, now that it has been repurposed for Sars-CoV-2, it will need to be put through especially stringent safety testing to rule out the risk of enhanced disease.
-
Once a Covid-19 vaccine has been approved, a further set of challenges will present itself. “Getting a vaccine that’s proven to be safe and effective in humans takes one at best about a third of the way to what’s needed for a global immunisation programme,” says global health expert Jonathan Quick of Duke University in North Carolina, author of The End of Epidemics (2018). “Virus biology and vaccines technology could be the limiting factors, but politics and economics are far more likely to be the barrier to immunisation.”
-
Because pandemics tend to hit hardest those countries that have the most fragile and underfunded healthcare systems, there is an inherent imbalance between need and purchasing power when it comes to vaccines. During the 2009 H1N1 flu pandemic, for example, vaccine supplies were snapped up by nations that could afford them, leaving poorer ones short. But you could also imagine a scenario where, say, India – a major supplier of vaccines to the developing world – not unreasonably decides to use its vaccine production to protect its own 1.3 billion-strong population first, before exporting any.
-
• This article was amended on 19 March 2020. An earlier version incorrectly stated that the Sabin Vaccine Institute was collaborating with the Coalition for Epidemic Preparedness Innovations (Cepi) on a Covid-19 vaccine.