Three years after the World Health Organization declared COVID-19 a pandemic on March 11, 2020, the fundamental question, where did COVID-19 start, remains a subject of intense debate. This virus, which brought the world to a standstill, closing borders, confining populations, devastating economies, and tragically claiming millions of lives, was initially detected in Wuhan, China, in late December 2019. Early investigations quickly connected the outbreak to the Huanan Seafood Wholesale Market. However, the swift actions of health authorities in Wuhan, which included sanitizing the market by January 1, 2020, inadvertently removed critical clues that could have pinpointed the exact origin of COVID-19.
The market was known to house exotic wildlife, including raccoon dogs and bamboo rats, species considered by many scientists as potential intermediary hosts in the virus’s journey from horseshoe bats – natural reservoirs for coronaviruses prevalent around Wuhan – to humans. This crucial link, however, remains unconfirmed due to the early cleanup and subsequent lack of transparency. From the outset, essential data has been missing from the investigation, and China’s reluctance to grant the WHO and other international researchers unrestricted access to remaining data has further complicated the quest to determine where COVID-19 truly started.
In the absence of definitive answers, two primary narratives have emerged, each vying to explain the origins of the COVID-19 pandemic.
One narrative, rooted in evolutionary biology, champions a natural, or “zoonotic,” spillover event. This theory posits that the virus naturally jumped from animals to humans, similar to previous outbreaks of zoonotic diseases. Conversely, the second narrative suggests a potential accidental lab leak from the Wuhan Institute of Virology. This high-security lab, located less than a kilometer from the Huanan market, is known for its research on dangerous pathogens, including coronaviruses. Proponents of the lab leak theory point to historical incidents of lab accidents in Taiwan, China, and Singapore, as well as near-misses reported in labs in the United States, including the University of North Carolina at Chapel Hill, as potential precedents.
Conspiracy theories, often fueled by political agendas, have also circulated, suggesting that COVID-19 could have been a bioweapon, intentionally released by either the US or China, depending on the theorist’s political leaning.
So, amidst these competing theories, what do we actually know about where COVID-19 started, and what does scientific evidence suggest?
The Prevailing Scientific View: Natural Spillover, but Evidence Gaps Remain
Currently, the majority of scientists and experts lean towards the natural spillover theory – the idea that the virus originated in animals and then transmitted to humans. However, the lack of transparency from China and the resulting scarcity of early data have prevented scientists from reaching a definitive conclusion. This evidentiary gap has, unfortunately, fostered an environment where conspiracy theories thrive, obscuring the search for the true start of COVID-19.
Lingering Questions and China’s Transparency
The question of where COVID-19 started has gained renewed urgency recently, spurred by headline-grabbing pronouncements from US intelligence agencies. In early February, the US Department of Energy’s intelligence branch stated, with “low confidence,” its assessment that the virus likely originated from a lab leak. This conclusion, based on undisclosed intelligence, was soon echoed by FBI Director Christopher Wray, who declared the bureau’s assessment that a “potential lab incident in Wuhan” was the “most likely” origin of the pandemic. This contrasts with the conclusions of four other US intelligence agencies and the National Intelligence Council, which previously assessed, also with “low certainty,” that the virus emerged naturally.
While the lab leak theory has become politically charged, particularly amidst US-China geopolitical tensions, concerns regarding Beijing’s lack of transparency concerning the origins of COVID-19 predate these recent pronouncements and stretch back to the very beginning of the crisis.
Beyond the removal of potential evidence at the Huanan market, China also faced criticism for not officially acknowledging human-to-human transmission of the virus until January 20, 2020. This delay occurred despite evidence suggesting that Chinese epidemiologists had begun employing advanced monitoring techniques in late December 2019 as infections from the novel virus escalated. A study published in the New England Journal of Medicine in March 2020 by Chinese researchers, analyzing data from 425 confirmed cases collected between December 10 and January 4, inadvertently highlighted this point.
“I call this 100 percent solid evidence China was hiding the fact that it knew it was contagious,” Chunhuei Chi, director of Oregon State University’s Center for Global Health, stated in an interview with Al Jazeera. He pointed out that sample collection beginning in early December indicated awareness of the disease much earlier than officially disclosed. “Had they disclosed the contagious nature earlier, we would not be in this pandemic at all,” Chi asserted, emphasizing the potential global impact of this delayed information.
Further fueling suspicions surrounding China’s actions were several other factors. The early identification of two distinct COVID-19 strains, “Lineage A” and “Lineage B,” suggested the virus had been circulating long enough to undergo mutation. Another point of concern was a US intelligence report, cited by the Wall Street Journal, alleging that three Wuhan lab workers sought hospital treatment in November 2019. While seeking hospital care for minor ailments is not unusual in China, the timing and nature of these reported illnesses added to the speculation.
China’s government also faced severe criticism for its handling of whistleblower doctor Li Wenliang, who was initially reprimanded for raising early alarms about the new virus. The subsequent silencing of voices and perceived obstruction of a WHO investigation in 2021 further damaged international trust and hindered the process of understanding where COVID-19 originated. The WHO investigation’s inconclusive results only deepened the mystery.
The Case for Natural Spillover: Mounting Evidence
Despite the persistent questions surrounding where COVID-19 started, and the lingering lab leak theory, a significant body of scientific evidence supports the natural spillover explanation. In May 2021, a group of prominent scientists, including evolutionary biologist Michael Worobey from the University of Arizona and virologist Jesse Bloom from the Fred Hutchinson Cancer Center in Seattle, advocated for further investigation into COVID-19’s origins. Their open letter published in the journal Science acknowledged the lab leak theory as a possibility but did not endorse it.
Since then, many of these scientists, including Worobey, have become more convinced of the natural spillover hypothesis, particularly following the publication of two significant studies in July 2022.
One study, spearheaded by Jonathan Pekar from the University of California San Diego, delved into the molecular epidemiology of COVID-19, examining the mechanisms of the virus’s emergence. This research offered a potential explanation for the simultaneous existence of the two early strains, Lineage A and Lineage B. The study suggested that viruses often undergo multiple unsuccessful attempts to jump to humans before a successful transmission occurs. The Huanan market, with its high foot traffic, became a central point of transmission. Lineage B likely first jumped to humans around November 18, 2019, at the market, followed by Lineage A’s jump “within weeks,” according to the study’s findings.
A second international study, published concurrently and led by Worobey, further reinforced the Huanan market’s role as the epicenter of the outbreak. By analyzing social media data and mapping the residential locations of early patients, the study revealed a significant clustering of cases around the market.
Adding to the weight of evidence for zoonotic spillover is the documented phenomenon of human-to-animal transmission throughout the pandemic. Cases of the virus spreading from humans to various animals, including minks, deer, cats, and dogs, have been reported globally. Notably, in Hong Kong, imported Syrian hamsters transmitted COVID-19 to their owners, likely contracting the virus during transit.
For numerous scientists, such as virologist Angela Rasmussen from the University of Saskatchewan, a co-author of the Worobey study, zoonotic spillover is currently the most plausible explanation for where COVID-19 started. In a Washington Post opinion piece co-authored with infectious-disease epidemiologist Saskia Popescu, Rasmussen stated that “No other explanation, including a laboratory origin at the Wuhan Institute or the Wuhan Center for Disease Control and Prevention, is consistent with the existing body of evidence.”
Other experts concur that zoonotic transfer is the most likely scenario but maintain a more cautious stance regarding definitively ruling out other possibilities. Lawrence Gostin, faculty director at Georgetown University’s O’Neill Institute for National & Global Health Law, told Al Jazeera, “There is quite considerable evidence of a naturally occurring spillover. And the vast majority of novel outbreaks start naturally.” However, he added a crucial caveat: “That is the most probable answer, but we will never know without greater access to both the market and the lab in Wuhan.”
The Lab Leak Theory: A Plausible Alternative?
Despite the compelling evidence for natural spillover, the lab leak theory continues to be considered a plausible, albeit less favored, alternative explanation for where COVID-19 started. Jesse Bloom, who co-authored the May 2021 letter advocating for further investigation, stated that both “a research-related incident and a natural infection remain plausible.” He emphasized that the lack of crucial early data makes it impossible to definitively determine which scenario is more likely.
Richard Ebright, a molecular biologist and director of the Waksman Institute of Microbiology at Rutgers University, has been a vocal proponent of considering the lab leak theory since the early stages of the pandemic. He expresses increasing skepticism about the market origin of COVID-19. “In the three years since that time, no new scientific data have become available relevant to the matter,” Ebright explained. However, he highlighted the emergence of “much new circumstantial evidence… on the high-risk virus enhancement research that was performed at the Wuhan Institute of Virology.”
The Wuhan Institute of Virology, the first lab in China certified to handle highly dangerous pathogens, including Ebola, is renowned for its extensive research on bat coronaviruses. This focus, coupled with the lab’s proximity to the initial outbreak and the inherent risks associated with handling and researching novel viruses, lends credence to the lab leak hypothesis for some experts.
Ebright argues that this “research-related spillover” is a more compelling explanation given the available circumstantial evidence. It is crucial to note that even proponents of the lab leak theory generally consider it to be an accidental event, with no credible evidence suggesting intentional release or bioweapon development.
Interestingly, the ongoing debate surrounding the origins of COVID-19 presents an opportunity for consensus on the critical need for enhanced safety protocols in both biolabs and wet markets globally. Thomas Bollyky, director of the Global Health Program at the Council on Foreign Relations, suggests, “There have been many lab leaks in the past, there have been many spillover events in the past – it is important to invest in measures around pandemic prevention in general on both sides.”
However, Bollyky acknowledges that achieving this goal necessitates “global cooperation,” a prospect increasingly complicated by geopolitical tensions surrounding the investigation into where COVID-19 started.
Science, Geopolitics, and the Search for Answers
Many scientists emphasize the critical importance of continuing the investigation into how COVID-19 started and spread to humans. Understanding the origins of the pandemic is crucial for learning vital lessons and strengthening global preparedness for future public health crises. The 21st century has already witnessed multiple zoonotic spillovers, including SARS, and the recent spread of bird flu among mammals raises further concerns about potential future pandemics.
“It’s important to continue to pursue this question,” emphasizes Oregon State University’s Chi. However, he also acknowledges the realistic possibility that “for the foreseeable future, we will not get to the bottom of it.”
This potential impasse, according to Bollyky, is less about scientific limitations and more about geopolitics. “The consequences from determining the origin of this pandemic are likely to be geopolitical – exclusively geopolitical,” he argues. “It is really a reputation issue,” particularly for China.
This month, Nature magazine reported the “quiet shelving” of the second phase of a WHO study into COVID-19 origins, despite warnings from the original research team about a rapidly closing “window of opportunity.” While WHO officials have disputed this characterization, the implications of this stalled investigation are significant.
The ongoing mystery surrounding where COVID-19 started extends far beyond China’s borders, impacting the entire world. As Gostin poignantly concludes, “We may never know for sure what caused the greatest human crisis of our lifetime. After all, we have suffered as a world.” He emphasizes the global need for “clear answers” to prevent future pandemics and ensure a more prepared and transparent global health system.
Source: Al Jazeera
