Coronavirus vaccine: when will it be ready? | World news | The Guardian - 0 views
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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.
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About 35 companies and academic institutions are racing to create such a vaccine, at least four of which already have candidates they have been testing in animals. The first of these – produced by Boston-based biotech firm Moderna – will enter human trials imminently.
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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
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Sars-CoV-2 shares between 80% and 90% of its genetic material with the virus that caused Sars – hence its name. Both consist of a strip of ribonucleic acid (RNA) inside a spherical protein capsule that is covered in spikes. The spikes lock on to receptors on the surface of cells lining the human lung – the same type of receptor in both cases – allowing the virus to break into the cell. Once inside, it hijacks the cell’s reproductive machinery to produce more copies of itself, before breaking out of the cell again and killing it in the process.
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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.
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Though nobody could have predicted that the next infectious disease to threaten the globe would be caused by a coronavirus – flu is generally considered to pose the greatest pandemic risk – vaccinologists had hedged their bets by working on “prototype” pathogens.
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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.
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Some of the Covid-19 vaccine projects are using these tried-and-tested approaches, but others are using newer technology.
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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.
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Clinical trials, an essential precursor to regulatory approval, usually take place in three phases. The first, involving a few dozen healthy volunteers, tests the vaccine for safety, monitoring for adverse effects. The second, involving several hundred people, usually in a part of the world affected by the disease, looks at how effective the vaccine is, and the third does the same in several thousand people. But there’s a high level of attrition as experimental vaccines pass through these phases.
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There are good reasons for that. Either the candidates are unsafe, or they’re ineffective, or both. Screening out duds is essential, which is why clinical trials can’t be skipped or hurried. Approval can be accelerated if regulators have approved similar products before.
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No vaccine made from genetic material – RNA or DNA – has been approved to date, for example. So the Covid-19 vaccine candidates have to be treated as brand new vaccines, and as Gellin says: “While there is a push to do things as fast as possible, it’s really important not to take shortcuts.”
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It’s for these reasons that taking a vaccine candidate all the way to regulatory approval typically takes a decade or more, and why President Trump sowed confusion when, at a meeting at the White House on 2 March, he pressed for a vaccine to be ready by the US elections in November – an impossible deadline.
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In the meantime, there is another potential problem. As soon as a vaccine is approved, it’s going to be needed in vast quantities – and many of the organisations in the Covid-19 vaccine race simply don’t have the necessary production capacity. Vaccine development is already a risky affair, in business terms, because so few candidates get anywhere near the clinic. Production facilities tend to be tailored to specific vaccines, and scaling these up when you don’t yet know if your product will succeed is not commercially feasible. Cepi and similar organisations exist to shoulder some of the risk, keeping companies incentivised to develop much-needed vaccines. Cepi plans to invest in developing a Covid-19 vaccine and boosting manufacturing capacity in parallel, and earlier this month it put out a call for $2bn to allow it to do so.
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The problem is making sure the vaccine gets to all those who need it. This is a challenge even within countries, and some have worked out guidelines. In the scenario of a flu pandemic, for example, the UK would prioritise vaccinating healthcare and social care workers, along with those considered at highest medical risk – including children and pregnant women – with the overall goal of keeping sickness and death rates as low as possible. But in a pandemic, countries also have to compete with each other for medicines.
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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.
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Outside of pandemics, the WHO brings governments, charitable foundations and vaccine-makers together to agree an equitable global distribution strategy, and organisations like Gavi, the vaccine alliance, have come up with innovative funding mechanisms to raise money on the markets for ensuring supply to poorer countries. But each pandemic is different, and no country is bound by any arrangement the WHO proposes – leaving many unknowns.