The origin of COVID-19 remains uncertain — still
Long ago Oscar Wilde cautioned, “The truth is rarely pure and never simple.” The COVID-19 pandemic is winding down, but the truth about the original source of the virus remains as contentious and elusive as ever.
Experts’ positions have hardened, but at least the facts about the two competing theories are clear enough today for the public to understand, even if the correct theory for the origin of COVID-19 remains uncertain.
The initial and for a time most popular explanation is known as the “zoonotic source” or more commonly, the “animal spillover theory.” This postulates that the virus originated in bats, then spread to an intermediary mammal and then leaped to infect humans. The main support for this theory is that the first cases of COVID-19 were believed to be from a wet food market in Wuhan, China, where many exotic mammals are caged in cramped, unsanitary conditions, conducive to pathogen spread. This aligns with the fact that the majority of pandemics occur due to transmission from animals. Specifically, the other two 21st century pandemics involving related coronaviruses — SARS CoV-1 in 2003 and MERS in 2012 — involved animal to human transmission.
Many virologists and epidemiologists are on record supporting this theory, including Dr. Paul Offit, the noted pediatrician and vaccine expert, who is this country’s leading authority on the history of vaccines. Offit’s opinion carries significant weight, but he has still not backed his opinion with dispositive evidence. The major weakness of the animal spillover theory is that for nearly five years researchers have been testing extensively for the virus in exotic animals such as civets, pangolins and raccoon dogs but to date they have found no evidence of COVID-19 in any of them. Until the virus is isolated in an intermediate host, the animal spillover theory is merely speculative.
The countertheory is that the virus emerged from a laboratory where work on viral transmission was being performed: the lab leak theory. The main support for this theory is that Wuhan, where the virus emerged, is the most important site in Asia for gain-of-function research (viral manipulation that can enhance transmission). The Wuhan virus laboratory is only several miles from the wet market, where the first cases appeared. Also concerning is that genetic analysis shows that the COVID-19 virus contains a binding region, known as a furin cleavage site, with a pattern that rarely occurs in nature.
Historically, lab leaks are occasionally responsible for dangerous pathogen outbreaks: in 1979, anthrax escaped from a Soviet laboratory and in a separate incident, smallpox leaked from a laboratory in Great Britain. Among those favoring the lab leak theory are members of the U.S. intelligence community, including officials in the FBI and Department of Energy, which is especially well-versed in laboratory procedure and biological research. Experienced science journalists such as Matt Ridley and Nicholas Wade, who have studied the question, also favor the lab leak theory. Unfortunately no specific leak site has been identified and nothing has been proven; the lab leak theory remains inferential, and it has gained considerable traction since it was dismissed early on as a conspiracy theory by public health officials.
It has become fashionable to use the term “conspiracy theory” to discredit anyone or any idea that is contrary to a mainstream belief or political view. Where once the term was reserved for such confections as faked moon landings or multiple shooters firing at former President John F. Kennedy from a grassy knoll, now it is a fashionable ad hominem way to discredit people without confronting and refuting their arguments through discourse.
Ironically, in the search for the source of COVID-19, there have been at least two documented actual — not theoretical — conspiracies: one by leading U.S. public health officials to debunk the lab leak theory and another by the Chinese government, which destroyed evidence in a probable attempt to hinder investigation of the source. When real conspiracies are in the air, scientists should consider retiring their use of the term “conspiracy theory” and stick to explaining facts. The best way to debunk the lab leak theory is to discover the animal that serves as the intermediary. Name calling is not a becoming feature of science, and does nothing to discredit the lab leak theory.
This lingering uncertainty prompts some researchers to mutter, “What difference, at this point, does it make?” Regardless of whether the virus turns out to have come from animal spillover, we still have to pay more attention to laboratory security. Similarly, confirmation of a lab leak would also still demand heightened scrutiny of wet markets. But there is another important principle at stake in the search for the origin of COVID-19: our faith in science. The theory that turns out to be correct will tell us what was true and what was not, whom we should have trusted and who was speaking out of ignorance — no matter how well-intentioned — and whether anyone was attempting to deceive the public. In an open society, these are not trivial issues, especially when trust in science has taken the beating it took during COIVD-19.
Two millennia ago, the Roman Stoic philosopher Seneca said that time discovers truth and that many discoveries are reserved for ages still to come. Perhaps Seneca was too optimistic for this inquiry, but this should not deter the pursuit of one of the most important scientific questions of the 21st century, “Where did COVID-19 come from?”