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Virologist Eric Snijder: ‘Vaccination will be going well in 2021’

The research group of Eric Snijder, Professor of Molecular Virology (LUMC), has been conducting research on coronaviruses for decades. Then in March this year their work accelerated at an unprecedented rate. The first new results are now available: insight into how the virus replicates.

This article appeared earlier in Leidraad, the free alumni magazine of Leiden University, which can also be read online (in Dutch).

Does he feel the pressure, now that the whole world is hoping for a solution, and is he working on it day and night? ‘Well the world has other problems too, not only viruses. But yes, we’re certainly working more overtime than usual. We’re trying to contribute what we can,’ is Snijder’s measured reply.

He does admit, however, that it was a strange sensation when his research field suddenly developed into a booming business over the past year. ‘It’s only now, when we have a global problem – something that virologists have been warning about for years – that the money really starts flowing in.’ 

Coronavirus had the world in its grip in a very short time. How did this happen?

‘This is due to many factors, such as the vast increase in mobility, the population density, the way we treat animals. And chance or bad luck also plays a part. When viruses jump to a new host, they often can’t get a foothold. But if they do, they’re very refined in how they operate. You could say that they know the password and PIN of our cells: they enter the cell, copy their genome, exit again, and then spread rapidly through the body. And we, the host, can’t cope with the speed at which that happens.’

About Eric Snijder

  • 1986 Biology, cum laude, Utrecht University 
  • 1991 PhD, cum laude
  • 2000 C.J. Kok Prize for research on nidoviruses 
  • 2007 Professor of Molecular Virology, Leiden 
  • 2012 member of the American Academy of Microbiology

Your group recently discovered how the new genome leaves the membrane structures where it’s created in the infected cell.

‘The virus makes a route out of the cell for itself. It would be great, of course, if we could block that route, so this discovery at least offers a new lead for developing antiviral drugs.’

The world seems to be completely focused on vaccines, and you don’t hear so much about antiviral drugs.

‘You need them both. Vaccines can prevent infections, but it takes time to develop them. Antiviral drugs can already be developed in advance, so you can have them ready to stop an epidemic before it gets going. It’s obviously better to prevent an infection than to cure it. But because you have to wait and see exactly which virus you’re dealing with, it takes at least one or two years to develop a vaccine. The decision was made fairly soon with SARS-CoV-2 – as the virus is officially called – to only mimic the spike protein and use this as the vaccine. It remains to be seen whether this will result in the best vaccine. And also the spike protein can change as immunity increases in the population, in order to evade the immune response and improve its chances of survival.’

Do antiviral drugs have a broader spectrum of activity than vaccines?

‘Yes. SARS-CoV-2 is 80 percent genetically identical to SARS-CoV-1. This means that in principle you can make antiviral drugs that work against several corona-viruses, or perhaps even all of them. Antiviral drugs are molecules that combat the virus itself by blocking the first phase of the infection. The survival rates that treatment now offers to HIV carriers are clear evidence that antiviral drugs can be extremely effective.’

How long will it be before you have effective antiviral drugs?

‘At least five to ten years. But then they’ll also be ready for immediate use if there’s the threat of an epidemic. That’s their advantage compared with vaccines.’

Why will it take so long?

‘To develop an antiviral drug, you first need a potentially useful ‘hit’: a chemical with a specific antiviral effect. There are three ways you can find this. At the moment, a CARE (Corona Accelerated R&D in Europe) robot in Leuven is screening 600,000 potential antiviral drugs. This will give a couple of hundred hits, but we won’t know whether the drug inhibits a viral function, or whether it affects the host cell and perhaps even kills it; this can’t happen, of course: the host needs to stay alive. It takes a long time to figure out exactly what’s going on.

‘The second approach focuses on designing a drug based on knowledge of the virus. But will it actually work in living cells? The third route is drug repurposing: testing drugs that already exist. The most well-known example of this is remdesivir, an anti-Ebola drug that also appears to have some effect against coronaviruses.’

Apart from medical interventions, what do we need to prevent pandemics like this?

As long as mobility stays so high, the world population continues to grow and we don’t change our diet, we will keep getting pandemics. Fifteen years ago, an outbreak like SARS-1 could just about be kept local, but now many more people and goods are flying around the world. So we need an integrated approach at the international level, drawing together the medical, social and economic perspectives. At the moment, everyone’s reacting from their own small corner of the world. That’s not going to help.’

What do you expect for next year?

‘In 2021, vaccination will be going well for some of the world population, but meanwhile the virus will still keep spreading. As it does so, just as now, a much larger number of people will become immune than will die.’

Text: Malou van Hintum

Accelerated research

As a result of the coronavirus pandemic, Eric Snijder is receiving more grant funding and can add at least ten more people to his research group. There is a large European CARE (Corona Accelerated R&D in Europe) grant for developing and extensively testing really good anti-coronavirus drugs, partly in preparation for future coronavirus outbreaks. And the Leiden crowdfunding campaign #wakeuptocorona has already raised over 1 million euros, thanks to numerous donors (and you can still donate!). An important use of this money will be to set up a second lab for coronavirus research, where the CARE project can also be carried out. ‘It has surprised me that basic research can appeal so strongly to the imagination,’ says Snijder. If only this money had been available sooner, he adds. ‘If there had been enough investment immediately after the first SARS epidemic in 2003, the antiviral drugs for the current virus would have been ready and waiting now.’ But that money was not available. Because SARS-1 died out and other viruses came onto the scene: Mexican flu, Ebola, MERS, Zika – but their impact did not extend (very far) into the European world. 

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