The lab leak theory continues to get attention, as the CIA recently assessed that the coronavirus more likely emerged from a lab than from nature with "low confidence" in its conclusion.
Five years ago today the World Health Organization called COVID-19 a pandemic for the first time. Much about the coronavirus was a mystery then - how exactly it spread, if we could treat it and whether we could prevent it. While the answers to those questions unraveled over the following years, a big one remains unanswered: What is the origin of COVID-19?
Theories about the origin of the coronavirus that has killed more than 1.2 million Americans have sparked strong debate - much of it seemingly partisan - in the U.S. and beyond. Leading theories include an animal host that transmitted COVID-19 to a human or an emergence from a laboratory leak.
Researchers strongly lean towards the theory that a person caught the virus from a wild animal at the Huanan Seafood Market in Wuhan, China. The leading suspect so far has been a raccoon dog.
But U.S. intelligence agencies are more split on the origin of COVID-19, with the CIA in January saying it assessed that the coronavirus more likely emerged from a lab than from nature. However, the spy agency said it had "low confidence" in its conclusion, and the agency's finding was not the result of any new intelligence.
"The lab leak hypothesis remains a topic of debate but lacks substantial scientific evidence," Pablo Penaloza-MacMaster, an associate professor of microbiology-immunology at Northwestern University Feinberg School of Medicine, said in an email. "To date, there is no verifiable data supporting the claim that SARS-CoV-2 emerged from a laboratory leak. Historical, genomic and evolutionary studies strongly suggest a natural origin."
The recent assessment certainly doesn't settle the debate over COVID-19's origin. China has been adamant that the lab leak theory is not supported by the data, though it has been accused of not sharing all the available data dating back to the early days of COVID-19's spread.
The World Health Organization is still calling on China to release more information about the virus.
"We continue to call on China to share data and access so we can understand the origins of COVID-19. This is a moral and scientific imperative," the WHO said in a statement in December 2024. "Without transparency, sharing and cooperation among countries, the world cannot adequately prevent and prepare for future epidemics and pandemics."
China's response was defensive.
"On the issue of COVID-19 origin tracing, China has always adhered to the spirit of science, openness and transparency, actively supported and participated in global scientific tracing, and resolutely opposed any form of political manipulation," Mao Ning, a spokesperson for China's Foreign Ministry, said following the WHO's statement.
Dr. Perry N. Halkitis, the dean of the Rutgers School of Public Health, says if China wasn't inclined to cooperate with the WHO previously, it certainly won't be in today's political climate, especially given the U.S. withdrawal from the WHO.
"At this moment, what's the motivation for China to come forward with that? I mean we are basically in this trade war with the world here in the United States," Halkitis says.
Of course, it is possible we will never know the origin of COVID-19. The "lack of comprehensive data from the early stages of the pandemic makes it difficult to precisely pinpoint the origin with certainty," Penaloza-MacMaster said. But he added that "it is not uncommon for viruses to jump from animals to humans, making the natural origin more likely."
So, does it matter if the world never uncovers the true origin of COVID-19?
Halkitis says it would be helpful to know the origin from a biological point of view.
"The more you know about a virus, the more power you have over it," he says. But is it essential knowledge? He says no.
"You can continue to focus on this or you can continue to figure out how it is that we're going to make it better, easier for people to get vaccinated, or make the vaccine more accessible, or make people more comfortable about the vaccine. Because at the end of the day, this thing is circulating, and it's going nowhere," Halkitis says. "So we're putting our energy in the wrong place."