A Response to Concerns About the Stance That COVID-19 Arose From A Natural Spillover Event
A response to concern about the rationale for my stance that the evidence does not currently support the idea SARS-CoV-2 escaped from a laboratory.
I recently lamented my frustration with an intentional campaign that cast doubt on scientific consensus on the origins of SARS-CoV-2, the virus that causes COVID-19. My comment responded to the article written by Yasmin Tayag on the source of the virus. Given the crisis and the misinformation swirling from every corner of the internet, I want to address the concerns expressed.
Please do not write or bother the person who wrote it. We all want and deserve good information, and so does this person. The mentioned misdirection and misinformation was the Corona Big Book. Behavior from US officials implied something supported the idea when that was not the case.
I appreciate your frustration with unqualified voices and misinformation circulating in this crisis and thank you for the prompt to examine how I came to my conclusion.
One correction I wish to make, though I suspect this was an unserious statement, is to clarify my experience. Indisputably, I am not an expert and defer to the opinion of my betters. Currently, I study public health viewed through the lens of biology and have also worked on two COVID-19 research projects, though these would not necessarily lend more credibility to my assessment.
Anyone may miss evidence, and if I have, I will amend my stance to reflect the new information. The following references are those that suggest nothing aside from a natural spillover event.
A laboratory escape is plausible — but we must be careful not to mistake plausible for proof something happened. Plausible and likely are not the same, so we must assess likelihood. On that I found, the most probable explanation is a natural spillover event, something that has both happened before and concerned scientists who feared it was inevitable.
Rational for rejecting laboratory escape hypothesis:
Fox, Dan. “COVID-19: The Big Questions That Remain.” Scientific American. https://www.scientificamerican.com/video/covid-19-the-big-questions-that-remain/ (July 30, 2020).
Andersen, Kristian G. et al. 2020. “The Proximal Origin of SARS-CoV-2.” Nature Medicine 26(4): 450–52.
- This study stated that natural origin was as likely as an escape, but was before he learned more about COVID-19 and related coronaviruses, which have features already seen in nature.
- Andersen later said, “There are lots of data and lots of evidence, as well as previous examples of this coming from nature,” and, “we have exactly zero evidence or data of this having any connection to a lab.”
Van Beusekom, Mary, and 2020. Scientists: “Exactly Zero” Evidence COVID-19 Came from a Lab. CIDRAP. https://www.cidrap.umn.edu/news-perspective/2020/05/scientists-exactly-zero-evidence-covid-19-came-lab (July 30, 2020).
- Referencing the same Andersen as the previous source, Van Beusekom writing for CIDRAP stated, “like other prominent virologists, [Andersen] says that he can’t completely rule out the possibility that the virus came from a lab, the odds of that happening are very small. He says the new coronavirus clearly originated in nature, ‘no question about it by now.’”
- Again, the author who first stated the two possibilities were at least equally likely had this to say considering additional evidence: “‘None of them match those of COVID-19, Andersen said, something Shi herself confirmed in a recent interview in Scientific American. ‘If she would have published a sequence for the virus and then this pops up, then we would have known it came from the lab,’ Andersen said. ‘There’s no evidence for this, but there is plenty of evidence against it.’”
- Andersen said the likelihood of a researcher becoming unknowingly infected with the coronavirus while wearing full PPE and then going to the Wuhan market is “fleeting compared to the alternative hypothesis, which is that we as humans, because we live amongst animals carrying these viruses — bats, but also many other intermediate hosts — and we don’t go around wearing PPE, we naturally get into contact with these viruses all the time.” — Occam’s Razor supports this.
- A scientist from the Center for Infection and Immunity at Columbia University stated the most plausible scenario is a “natural zoonotic spillover,” adding that serology studies have shown that some people in China living near bat caves have antibodies against bat SARS-like coronaviruses in their blood, “suggesting that people are exposed to related viruses in the course of their daily lives, so it’s not implausible that SARS-CoV-2 emerged in humans through a chance encounter between a human and a wild bat or some other animal.”
Morens, David M. et al. 2020. “The Origin of COVID-19 and Why It Matters.”
- “Scientists have warned for decades that such sarbecoviruses are poised to emerge again and again, identiﬁed risk factors, and argued for enhanced pandemic prevention and control efforts. Unfortunately, few such pre-ventive actions were taken resulting in the latest coronavirus emergence detected in late 2019 which quickly spread pandemically.
The critical importance of the origin is that if it’s a laboratory accident, then that changes how we approach prevention of future incidents. This was something scientists warned about for over a decade. Thousands of coronaviruses exist in bats around the world and preventing another pandemic will require observing the evidence and nothing else.
- The risk of similar coronavirus outbreaks in the future remains high.
- In addition to controlling the COVID-19 pandemic, we must undertake vigorous scientiﬁc, public health, and societal actions, including signiﬁcantly increased funding for basic and applied research addressing disease emergence, to prevent this tragic history from repeating itself.
- “Ominously, bat-to-human transmission of SARS-like viruses has already been detected, perhaps representing pandemic near-misses. Even the more genetically distant SADS-CoV infects cells of humans and numerous other vertebrates, raising concern about indirect coronavirus emergences.
- “This seems to have occurred with the bat-to-camel-to-human emergence of MERS, and possibly with SARS-CoV emergence into humans, which may have resulted from bat virus infection of masked palm civet cats (Paguma larvata), with subsequent human spillover. As a byproduct of the important international surveillance work described above, in 2017, the therapeutic benefit of the antiviral drug remdesivir was suggested; it is now, in 2020, being widely used to treat persons infected with SARS-CoV-2.”
- Morens has added insightful commentary on pandemics before: Morens, David M., Jeffery K. Taubenberger, Hillery A. Harvey, and Matthew J. Memoli. 2010. “The 1918 Influenza Pandemic: Lessons for 2009 and the Future.” Critical Care Medicine 38(4 Suppl): e10-20.
Fan, Yi, Kai Zhao, Zheng-Li Shi, and Peng Zhou. 2019. “Bat Coronaviruses in China.” Viruses 11(3): 210.
- “Thus, it is highly likely that future SARS- or MERS-like coronavirus outbreaks will originate from bats, and there is an increased probability that this will occur in China.
- “Therefore, the investigation of bat coronaviruses becomes an urgent issue for the detection of early warning signs, which in turn minimizes the impact of such future outbreaks in China.”
- “The purpose of the review is to summarize the current knowledge on viral diversity, reservoir hosts, and the geographical distributions of bat coronaviruses in China, and eventually we aim to predict virus hotspots and their cross-species transmission potential.”
Ge, Xing-Yi et al. 2016. “Coexistence of Multiple Coronaviruses in Several Bat Colonies in an Abandoned Mineshaft.” Virologica Sinica 31(1): 31–40.
- “Additionally, the surveillance identified two unclassified betacoronaviruses, one new strain of SARS-like coronavirus, and one potentially new betacoronavirus species.”
- “Furthermore, coronavirus co-infection was detected in all six bat species, a phenomenon that fosters recombination and promotes the emergence of novel virus strains. Our findings highlight the importance of bats as natural reservoirs of coronaviruses and the potentially zoonotic source of viral pathogens.”
Wang, Ning et al. 2018. “Serological Evidence of Bat SARS-Related Coronavirus Infection in Humans, China.” Virologica Sinica 33(1): 104–7.
- “Our study provides the first serological evidence of likely human infection by bat SARSr-CoVs or, potentially, related viruses. The lack of prior exposure to SARS patients by the people surveyed, their lack of prior travel to areas heavily affected by SARS during the outbreak, and the rapid decline of detectable antibodies to SARS-CoV in recovered patients within 2–3 years after infection strongly suggests that positive serology obtained in this study is not due to prior infection with SARS-CoV (Wu et al. 2007).”
- “The 2.7% seropositivity for the high risk group of residents living in close proximity to bat colonies suggests that spillover is a relatively rare event, however this depends on how long antibodies persist in people, since other individuals may have been exposed and antibodies waned.”
Callaway, Ewen, Heidi Ledford, and Smriti Mallapaty. 2020. 583 Six Months of Coronavirus: The Mysteries Scientists Are Still Racing to Solve. Nature Publishing Group. https://www.nature.com/articles/d41586-020-01989-z (July 30, 2020).
- “What is the origin of the virus? Most researchers agree that the SARS-CoV-2 coronavirus probably originated in bats, specifically horseshoe bats. This group hosts two coronaviruses closely related to SARS-CoV-2. One, named RATG13, was found8 in intermediate horseshoe bats (Rhinolophus affinis) in the southwestern Chinese province of Yunnan in 2013. Its genome is 96% identical to that of SARS-CoV-2. The next-closest match is RmYN02, a coronavirus found in Malayan horseshoe bats (Rhinolophus malayanus), which shares 93% of its genetic sequence with SARS-CoV-29.”
- “A comprehensive analysis10 of more than 1,200 coronaviruses sampled from bats in China also points to horseshoe bats in Yunnan as the probable origin of the new coronavirus. But the study doesn’t exclude the possibility that the virus came from horseshoe bats in neighbouring countries, including Myanmar, Laos and Vietnam.”
- “The 4% difference between the genomes of RATG13 and SARS-CoV-2 represents decades of evolution. Researchers say this suggests that the virus might have passed through an intermediate host before spreading to people, in the same way that the virus that causes SARS is thought to have passed from horseshoe bats to civets before reaching people. A few candidates for this animal host were put forward early in the outbreak, with several groups homing in on pangolins.”
One Health Institute. 2018. USAID PREDICT Findings & Implications. https://www.youtube.com/watch?v=C7h0LxYjxks (July 30, 2020).
On April 20, 2020,
I wrote a response to the idea that this did not spillover naturally, though this also addresses a related but different idea that this was engineered. Much of it remains relevant, so I include that.
All evidence currently suggests this to be a virus that spilled over naturally, and scientists warned this was a potentiality in several papers [1–3]. Scientists have sequenced the virus around the globe, and nothing suggests manipulation or intentional release at this time.
Circumstantially, the viral load carried by bats in southern China increases in the Autumn, increasing the chances for spillover.
Admittedly I’m speculating, but I suspect SARS-CoV-1 (Nov 2002) and SARS-CoV-2 (Nov 2019) spilling over when they did — roughly the same time of year and potentially similarly — relates to the increased viral richness among bats in that region, during Sept, Oct, and Nov.
Emerging infectious diseases of zoonotic origin have risen steeply over the last century, without human intent , and developing regions have the highest risk. A presentation on USAID PREDICT research stated we now see three new emerging infectious diseases per year . (@Dr Jonna Mazet, please correct me if I am incorrect).
Thus, we have: an outbreak that aligns with observed emergence trends; caused by a virus that scientists feared would spill into the human population [1–3,5]; during the season where increased viral richness appears in bats from a likely location and reservoir;3 and in a manner, other Coronaviruses have done so in the past 
1. doi: 10.1038/nm.3985;
2. doi: 10.3201/eid1906.121648
6. Article Epidemiologic clues to SARS origin in China
8. doi: 10.14745/ccdr.v43i10a03
I hope this sheds light on how I formed my opinion.
These do not disprove an escaped virus. No evidence supports the idea at this time, and if evidence ever supports the idea, my position will change to reflect that information.
Communications in this crisis have been troubling, and the public trust, eroded. The nature of the document, Corona Big Book, portrays a deeply disturbing indifference to the need and right of the American people to have the truth.
Sen. Tom Cotton repeatedly promoted the idea that this was a bioweapon or laboratory accident, a view he admitted lacked any evidence. The document came out well after multiple fields had concluded it likely arose naturally. Claims about this appeared the moment the virus appeared, even when it was too early to draw any conclusions.
Accidental releases have happened in the past. They have also had real-life consequences, which shows this was a plausible idea. The result of having real-life examples is that we know what it should look like if this were a laboratory accident, and so far, the telltale signs have failed to materialize.
Regardless of culpability — something we may explore with no less justice at a later time — we rescue people from a burning building before we worry about the arsonists identity. Understanding how much death we could have prevented has profoundly affected me and led me to write about the subject.
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