Human trials will begin imminently – but even if they go well, there are many hurdles before global immunisation is feasible
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.
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.
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.
But
there is another reason for the head start. 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. “The speed with which we have [produced these
candidates] builds very much on the investment in understanding how to
develop vaccines for other coronaviruses,” says Richard Hatchett, CEO of
the Oslo-based nonprofit the Coalition for Epidemic Preparedness Innovations (Cepi), which is leading efforts to finance and coordinate Covid-19 vaccine development.
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.
Coronavirus vaccine: when will it be ready?
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