The U.S. intelligence community was unable to reach a conclusion about the origins of COVID-19 after a 90-day review of available data and interviews with top health experts and officials.
If anyone was surprised about the inconclusive results, it was not those same health experts and officials. Those with experience hunting viruses in their natural habitats know just how difficult it is to track their origins.
Many had said from the beginning that there is insufficient evidence to pinpoint the moment in which the coronavirus infected its first human victim — and, based on experience with previous novel pathogens, the evidence is almost certain never to be found.
“It was obvious to many of us that based on the information they had, it was going to be incomplete,” said Michael Osterholm, director of the Center for Infectious Disease Research and Prevention at the University of Minnesota. “The level of information you need from the time that a spillover might have occurred or the time a leak might have occurred is in relatively short supply.”
The review by American intelligence agencies will be unsatisfying for everyone, whether they are inclined to believe the virus came from an animal known as a reservoir host and infected the first humans in a natural setting — something most health experts believe is the most likely explanation — or that the global pandemic is the result of a lab leak at a facility in Wuhan, China.
The Chinese government has not helped, either with the American review or a separate investigation undertaken by the World Health Organization, criticizing those inquiries as efforts to cast blame for a pandemic that has killed millions across the globe. But even with full cooperation, finding the true origin of the novel pathogen would have been highly unlikely.
“We will likely be left in suspension on this for years, unfortunately,” said Eric Topol, an expert in molecular medicine at the Scripps Research Translational Institute in California.
The moment when a virus jumps from an animal to a human, known as a spillover event, is almost impossible to identify. If the virus itself is unknown to science before it infects its first victim, health care professionals do not have the ability to test for it; if the victim is treated in a hospital setting, the doctors do not know what they are looking at.
Even in retrospect, once a pathogen becomes a global public health threat, finding evidence of its origins rarely occurs. After half a century of occasional outbreaks in African nations, scientists have never firmly established the reservoir host of the Ebola virus, though a certain species of bat is the likeliest suspect. Decades of investigation have not uncovered the spillover event that started the global HIV/AIDS pandemic.
More recently, Osterholm pointed to SARS, which killed at least 770 people in the early 2000s, or MERS, which killed at least 880 people a decade ago, mostly on the Arabian Peninsula.
In both cases, much is known about how the viruses — also coronaviruses — spilled over into humans: SARS in China’s Guangdong province, MERS from camels in Jeddah, Saudi Arabia. But the exact moment of spillover in each case are events lost to history.
In the case of COVID-19 virus, also known as SARS-CoV-2, there is evidence that the pathogen was circulating and infecting people months before the first recognized outbreak in Wuhan in late December 2019. But there is no set of blood samples to test in hindsight or evidence of widespread outbreaks of a particularly suspicious respiratory disease that might act as a blinking red light.
“We’ll never know. No one has test results from back then. No one has a smoking gun set of outbreaks,” Osterholm said. “This surely needs more study, and hopefully more info forthcoming from the Chinese lab experts, from the people involved in the community-based studies.”
Public health experts say the lack of conclusive evidence should not take away from the persistent threat of lab leaks, which exist around the world. Scientists in both the United States and Russia have been infected in the past with deadly diseases like Ebola because of accidental needle pricks and other causes.
“No matter what actually happened, it’s kind of besides the point,” said Tom Frieden, who led the Centers for Disease Control and Prevention during the Obama administration and now runs Resolve to Save Lives, a global health nonprofit.
“We know that lab accidents happen and we need a better global approach to reducing the risk,” Frieden said. “We know that spillover happens and we need a better global approach to reducing the risk. Not nearly enough is done on either of these. No matter what happened or didn’t happen in Wuhan, we need to do better at preventing both lab releases and spillover all over the world.”