The dangers of virus hunting

DEEP VZN aimed to discover viruses in wildlife that could threaten humans, but the risks weren’t worth the rewards.

A year ago I wrote about the question of DEEP VZN, a $125 million USAID program to track down viruses that might cause the next pandemic. For a long time, the US has funded work like this, and the case for it is pretty simple: Why don’t we find the next pandemic before it finds us? But for just as long, virologists have been pointing out that the case for this kind of work is actually tenuous: There are millions of viruses out there, and it’s hard to guess which ones will actually pose a threat to us. Leaders in the field complained in a 2018 commentary in Nature that viral discovery was “of little practical value.”

But the calculations are actually worse than that. With increasing awareness of biosafety and biosecurity issues in the aftermath of the Covid-19 pandemic came concern that viral discovery work can actually create serious risks. Now, according to reporting from the British Medical Journal (BMJ), these worries have prompted the US government to reevaluate — and ultimately cancel — DEEP VZN.

That decision is a good sign about how the Biden administration and Congress are approaching pandemic preparedness. Virology has done tremendous good in our world and will continue to do so — but the specific practice of actively searching out potentially dangerous new viruses wasn’t a good idea. “I’m glad we’re reevaluating some of these programs from a biosafety perspective,” Syra Madad, an epidemiologist at Boston University, told me. “These types of programs come with pretty significant risks and challenges.”

As biosecurity expert Andrew Weber told the Bulletin of the Atomic Scientists: “The grave risks are hardly justified by the meager potential benefits.”

What could go wrong with viral discovery work?

The first such risk is that of accidents: While trudging out to remote corners of the world looking for viruses, or while bringing such viruses back to the lab to study, scientists could be accidentally exposed — and then unwittingly expose others.

That’s not a hypothetical: Instead, in viral discovery research in remote regions, high-risk exposures became practically a routine phenomenon. Thai researchers doing US-backed virus-hunting work were repeatedly bitten by bats, a Washington Post story earlier this year reported. Ultimately, they concluded that the work they were doing posed too great a risk to the public to continue.

“To go on with this mission is very dangerous,” researcher Thiravat Hemachudha, who supervised the expeditions, told the Washington Post. “Everyone should realize that this is hard to control, and the consequences are so big, globally.” Eventually, he told his American funders that he was done: The work had produced no benefits for Thailand and put his researchers at enormous risk.

The Thai team’s decision was part of a larger rethinking of such work in the aftermath of Covid-19, which provided a vivid reminder of how fast a pandemic can escalate from a single exposure to a worldwide catastrophe that leaves millions dead. “Leave the bats alone,” Johns Hopkins professor Steven Salzberg argued in 2021, adding: “Why do we give grants to scientists to go into bat caves, collect bats infected with deadly viruses, and bring them back into the midst of cities?”

Of course, with comprehensive global planning and coordination, we can reduce the risks of spreading the viruses that we study. But the second major risk of viral discovery work can’t be similarly mitigated, because it becomes a problem not if the work goes wrong, but if it goes precisely as planned.

Say that you can, through viral discovery research, learn of a virus as contagious and as deadly as the 1918 influenza — and which, unlike the 1918 influenza now, humans have no preexisting immunity to. “The clear worry is that if you publish information on a pathogen that is of pandemic potential, we know that we have nefarious actors out there that may be willing to use that to harm humans, animals, and the environment,” Madad told me.

Learning about a new deadly pathogen might help us develop vaccines against it, which would be great. It also might hand a blueprint to any group that wants to know how to cause mass death — which is not so great.

That possibility might sound speculative. Unfortunately, it is chillingly grounded. “History has shown that there are groups that will try to do that,” Madad told me. In 1995, Japanese doomsday cult Aum Shinrikyo carried out a deadly sarin gas attack on the Tokyo subway and a series of other attacks with chemical weapons and biological weapons, including anthrax.

The man who produced the sarin gas for the terrorist attacks was a Kyoto University-trained virologist, but luckily he couldn’t access any truly deadly bioweapons — because we don’t know of any. Yet.

“Today, we don’t have a good idea of which particular viruses are extremely likely to cause a pandemic if introduced into humans, and for this reason, it’s hard for terrorists, nihilists — it’s hard for these people to currently cause pandemics for lack of knowing which viruses would do the job,” MIT biologist Kevin Esvelt told me. “Insofar as we find a bunch of candidates from nature and characterize them in the lab, we are doing these people’s work for them.”

It’s a good thing that terrorists don’t know any good viruses they could unleash to cause mass casualty events. Discovering such viruses might help the world defend itself against them — but it might also be the reason the world ends up needing to defend itself against them.

Flaring tempers in the virology world

Many virologists had long pointed out that viral discovery work is not very useful, but others in the field were still frustrated by the cancellation of DEEP VZN, feeling that the whole field was being unjustly condemned as dangerous.

“A lot of virologists definitely feel like they’ve been attacked, the whole field has been demonized — even virologists who haven’t done anything dangerous at all,” Esvelt told me. He added emphatically, “This is not about dumping on virology — 99.9 percent of virological research is lifesaving. It just so happens that this particular one of attempting to credibly identify pandemic viruses is massively net negative.”

It’s important that the call to cancel DEEP VZN should be the first step of an effort to focus on better pandemic prevention work, instead of a movement to give up and stay home. There is a lot of incredibly important virological work that needs doing. It may be courting trouble to go out and find viruses in remote caves that have never crossed over into humans at all, but it’s crucial to study and prepare for viruses already crossing over into humans at human-wildlife interfaces.

And I’d argue that it’s also important that we praise and commend scientists like Thiravat Hemachudha, whose team spent a decade braving bat bites for science and then decided to stop. It would be extraordinarily tough to, after a career of doing backbreaking research, change your mind and say, “The benefits here don’t outweigh the risks.” Yet that’s what Hemachudha did.

The true spirit of science is a willingness to change your mind, to rethink your most fundamental assumptions, and to accept you were on the wrong track. Instead of condemnation and anger, we can look back at virus hunting with a determination to learn from what went well and what was unnecessarily risky, and to craft a program better designed to prevent the next pandemic.