Another round of debate about the origin of Covid-19 sparked this week when the Wall Street Journal reported that the US Department of Energy concluded with “low confidence” that the virus escaped a laboratory in China, in a classified document.

However, officials declined to corroborate the Journal’s reporting. “We can neither confirm nor deny the item at issue in the WSJ story,” an Energy Department spokesperson told Vox in an email.

The new verdict echoes a similar conclusion from the FBI, but runs counter to that of four other federal agencies and a national intelligence panel, which concluded the SARS-CoV-2 virus that causes Covid-19 jumped into humans from a natural exposure to an infected animal.

The discussions around the origins of Covid-19 remain acrimonious among politicians and scientists. Even within the US government, different agencies can’t agree. National security adviser Jake Sullivan told CNN on Sunday, “Right now there is not a definitive answer that has emerged from the intelligence community on this question.”

Nonetheless, figuring out where the virus came from is still a high priority for President Joe Biden. “The president believes that it is important that we get to the bottom of this,” said White House press secretary Karine Jean-Pierre on Monday. “We need to be prepared for potentially another pandemic.”

Yet now, more than three years out from the first reports of a strange pneumonia spreading in Wuhan, China — with much of the initial evidence long gone and little cooperation from the Chinese government — the investigations are unlikely to reach a definitive conclusion about how the pandemic began. Politically, it’s key to establishing how much blame falls on China’s government for its handling of Covid-19. It might also reveal which factors are most likely to trigger another outbreak.

However, experts say that even without an answer, there are things we can and should begin doing now to mitigate the risks of future pandemics. While both scenarios are not equally likely, they are alarmingly plausible, and the chances that either pathway could launch another international calamity are growing.

The US government found little so far in its search for the origins of Covid-19

The US government is pursuing a multi-pronged search for how the virus that causes Covid-19 emerged. Science agencies like the National Institutes of Health are investigating, but intelligence agencies are also pulling their own threads.

Back in 2021, Biden ordered a “90-day sprint” from the intelligence community to examine where SARS-CoV-2 came from. The resulting report, however, was inconclusive. Biden vowed to continue studying the question nonetheless. “The world deserves answers, and I will not rest until we get them,” he said in August 2021.

Since then, government agencies with intelligence and biology capabilities have kept looking. Though the Department of Energy may not be the first federal institution to come to mind to investigate Covid-19’s origins, it has a lot of resources suited to the task.

The Energy Department operates 17 national laboratories whose work spans from nuclear weapons to biosafety. In response to Covid-19, the agency created the National Virtual Biotechnology Laboratory, and last year published a report on how it would respond to future pandemics. The agency also has its own intelligence and counterintelligence office including a “Z-division” tasked with covert studies of nuclear, biological, and chemical threats.

“President Biden specifically requested that the national labs, which are part of the Department of Energy, be brought into this assessment,” Sullivan said on CNN.

According to the Wall Street Journal, the “Energy Department’s conclusion is the result of new intelligence,” though officials didn’t elaborate on what that intelligence showed. CNN reported that the Energy Department’s verdict was built on information about ongoing coronavirus research at the Chinese Centers for Disease Control in Wuhan, China. This is a different institution from the Wuhan Institute of Virology, a laboratory that was also considered as a possible source of a lab leak of the SARS-CoV-2 virus.

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When Vox asked for comment, several national laboratories deferred to the Department of Energy’s press office.

“As the WSJ article points out, the DOE report is classified so there is nothing we can say in response to it or for related stories,” said a spokesperson for Pacific Northwest National Laboratory in an email.

However, other US intelligence divisions think a natural origin is the more plausible root of the pandemic. A team of scientists last year also reported that they found more evidence that the virus leapt into humans at the Huanan Seafood Wholesale Market in Wuhan, where the earliest known cases clustered.

Meanwhile, US lawmakers have also conducted their own investigations. Republicans on the Senate health committee issued an interim report in October 2022 that concluded “the COVID-19 pandemic was, more likely than not, the result of a research-related incident.”

All of these assessments, however, acknowledge their findings are mired in uncertainty and that major gaps remain in both the lab leak and natural origin hypotheses. So far, no one has figured out which animal served as the intermediate host for SARS-CoV-2 before it infected humans, and scientists have yet to find a direct ancestor of the virus in nature. The most similar virus was found in bats in Laos more than 1,500 miles away from Wuhan.

At the same time, no evidence has been found that the Wuhan Institute of Virology or the Chinese Centers for Disease Control had live SARS-CoV-2 or a progenitor virus in their possession. No investigation has found that the virus was engineered or created as a bioweapon.

The complication for both of these stories is the Chinese government’s intransigence. Investigators from around the world have complained that the Chinese government is not cooperating, blocking access to people involved in the early response and not sharing records from the initial outbreak.

“China’s cooperation most likely would be needed to reach a conclusive assessment of the origins of COVID-19,” US intelligence agencies noted in their 2021 report. “Beijing, however, continues to hinder the global investigation, resist sharing information and blame other countries, including the United States.”

The risk of more lab leaks and more natural spillovers is mounting

While investigators may never get a sharper picture of how SARS-CoV-2 erupted, the risks of future pandemics — from laboratories and from natural spillovers — is mounting.

“Both situations are certainly possible. Both of those risks are increasing,” said Milana Boukhman Trounce, director of biosecurity and pandemic resilience at Stanford Medical School.

The odds of a virus jumping from animals to humans has surged in the past several decades. The risk is increasing further as humanity encroaches into plains, forests, and swamps, raising the odds of encountering a new pathogen. Even prior to Covid-19, scientists warned for years that a coronavirus from bats could infect humans via an intermediary. The world’s growing appetite for meat is also worsening pandemic risks as high-density farms with nearly identical cattle, pigs, and chickens packed close together proliferate. These facilities can incubate dangerous pathogens, allow them to spread rapidly, and potentially infect people.

Human activity is increasing the likelihood of both of these scenarios, so a spillover is hardly a “natural” event.

With respect to laboratories, Covid-19 revealed that there are yawning oversight gaps in how scientists study dangerous pathogens and what kinds of experiments they run. Scientists at the Wuhan Institute of Virology, for instance, conducted coronavirus research using lower safety standards than most scientists would consider safe for viruses that can spread through the air, as I previously reported. Some researchers have alleged that the institute was also engineering viruses to become more infectious. This type of research, called gain of function research, could help scientists develop countermeasures to a disease, but it also means that a more dangerous virus could escape a lab.

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And viruses have leaked from labs. A scientist at the Chinese National Institute of Virology in Beijing in 2004 was infected with SARS, triggering an outbreak that put 1,000 people under quarantine or medical supervision.

In the wake of Covid-19, many more countries are building out virus research facilities, and the barrier to entry for conducting high-risk experiments is dropping. “Science is more democratized, and the ability to essentially engineer infectious organisms to make them more infectious and more deadly is out of the box,” said Trounce.

To counter the threat of a natural virus spillover, governments will need to limit destruction of ecosystems and restrict the wildlife trade. They will also have to improve animal welfare and disease screening on farms.

And to stop a future lab leak, Trounce said scientists will first have to create norms that govern safety standards, the kinds of experiments they perform, and openness about their work. Right now, there are no consistent guidelines for working with dangerous pathogens around the world and no incentive to disclose if there’s been an accident. With governments more concerned about managing their reputations, it’s scientists that will need to take the lead in being forthright about their work. “Our collective safety is [enhanced] by building openness and transparency and trust in scientific community,” Trounce said.

There are also strategies that could prevent a pandemic regardless of the source. Virus surveillance and screening people at high risk of exposure could catch an outbreak in its early stages. Developing better indoor air filtration and ventilation could also interrupt the transmission of airborne infectious diseases.

The ultimate goal is to break out of the “panic, fund, forget” cycle that often emerges after a crisis. With the global Covid-19 death rate falling to levels not seen since early 2020, the worry is that attention and money will shift away from preventing the next viral catastrophe. Tracing the roots of Covid-19 is still an important scientific and political task, but it’s far more urgent to halt the next pandemic before it ignites.