WHO’s Scientific Advisory Group for the Origins of Novel Pathogens (SAGO), set up soon thereafter for a fresh investigation, failed to gain access to relevant Chinese data. The Chinese government’s equivocation, the fragmented, obfuscatory facts it provided, its punitive measures against those demanding greater transparency, and the suppression of information have only created growing suspicion.

The lab leak theory has not gone away. Earlier this year, the director of the Federal Bureau of Investigation (FBI), Christopher Wary, said that the agency assessed that the origin of the pandemic was a lab leak from Wuhan. Last month, Robert Kadlec, a former US assistant secretary for health and human services, serving as a White House aide on biodefence and epidemic response issues, suggested that a WIV scientist, Zhou Yusen, could have been the source of the virus leak and might have been murdered for it. On February 24, 2020, Yusen had filed a patent for a SARS-CoV-2 vaccine, within weeks of the outbreak of the virus, leading to Kadlec’s conclusion that Yusen had been working on the vaccine for quite some time. He was believed to have been confronted by the Chinese authorities after the virus outbreak and allegedly died mysteriously soon thereafter.

The prohibition to develop, produce, stockpile, acquire or retain biological agents and toxins is not absolute under the 1972 Biological and Toxin Weapons Convention (BTWC), which is a weak instrument with no verification of compliance. States party to the Convention are allowed to carry out research for prophylactic, protective or other peaceful purposes, without specifying permissible types and quantities of pathogens. Advances in genetic engineering allow States to maintain their biological weapons programme. No progress was made on strengthening the Convention by improving compliance or prescribing procedures for investigating intentional or accidental lab leaks, despite its 9th review conference held in the aftermath of the pandemic outbreak.

EcoHealth Alliance was granted funds for risky “gain of function” research despite a US funding moratorium on such research for biosafety and biosecurity reasons. The WIV research involved intentionally altering a coronavirus to make it more virulent, contagious, and pathogenic for the human population through a process of recombination.

China’s biological weapons programme had come to notice long before SARS-CoV-2. Dany Shoham of the Begin-Sadat Center for Strategic Studies, Bar Ilan University, Israel, profiled ’China’s Biological Warfare Programme: An Integrative Study with Special Reference to Biological Weapons Capabilities’, in the April–June 2015 issue of the Journal of Defence Studies published by the Institute for Defence Studies and Analyses, which mentioned the WIV as a facility affiliated with the People’s Liberation Army.

US funding continued despite a January 2018 report by the state department inspectors about operating deficiencies at the WIV. Besides, the department’s latest (2023) unclassified report titled ‘Adherence to and Compliance with Arms Control, Non-proliferation, and Disarmament Agreements and Commitments’ stays with its decade-long assessment that China continues “to engage in biological activities with potential biological warfare applications”, doubting its compliance with BTWC. The American position on the origin of the virus has been curiously ambivalent. Enraged by insinuations about wilful or inadvertent leakage, the Chinese foreign office charged that the provenance of the virus was from the US. Former US President Donald Trump began to refer to SARS-CoV-2 as the Wuhan virus. The then US presidential candidate Joe Biden reportedly called this “xenophobic” and the liberal press in the US largely agreed.

On becoming President, Joe Biden ordered an assessment of the differing origin theories. The investigations that followed failed to find the smoking gun. The US Intelligence Council stated that China did not develop the virus as a biological weapon but its lack of cooperation prevented a diagnosis of either hypothesis, natural transmission or lab-related. Part of the US compulsion was to not upset China and the other was to avoid pointing a finger at its own agencies for lack of due diligence in contracting research to WIV.

The origin of SARS-CoV-2 is a continuing mystery. The quest to solve it will continue as long as the unanswered questions remain.

Jayant Prasad has been the former director general of IDSA and member of the UNSG’s Advisory Board on Disarmament Matters. The views expressed are personal