More than half a year has passed since a joint World Health Organisation (WHO) and Chinese team completed initial studies into the origins of Covid-19.
Yet, the world is no closer to finding out how this contagion started.
Late last month, international experts on the WHO team warned that time is running out.
Antibody levels in the first patients who contracted the virus are rapidly waning, so it could soon be impossible to pinpoint the first cases of Covid-19, they wrote in an editorial published in Nature on Aug 25.
Investigations have stalled, said the 11 scientists, urging global leaders and the scientific community to take action.
"The window of opportunity for conducting this crucial inquiry is closing fast: any delay will render some of the studies biologically impossible. Understanding the origins of a devastating pandemic is a global priority, grounded in science," they said.
The problem is, what was supposed to be a scientific inquiry has been hijacked by politics, with Beijing and Washington arguing about whether the coronavirus leaked from a laboratory.
As relations between both countries continue to sour, tensions have poisoned this key area of scientific study.
Some politicians in Washington have alleged that the coronavirus had escaped from a Chinese lab in Wuhan, while Beijing has countered with claims that the virus had instead leaked from American labs, including the US military base Fort Detrick.
Despite the lack of evidence, this lab-leak hypothesis has dominated headlines, distracting from perhaps more legitimate lines of scientific inquiry.
As Dutch virologist Marion Koopmans, one of the co-authors of the Nature editorial, told The New York Times recently: "We were getting a little concerned that there really is virtually no debate about the bulk of the recommendations that are not related to the lab hypothesis, and of course there's a lot of discussion of the lab story, particularly coming from the US.
"Our concern is that because of that emphasis, the (other recommendations do) not get any more attention."
What the science tells us
It is hard to overstate the importance of getting an accurate handle on how the current pandemic started.
Scientists have said that the knowledge would be instrumental in preventing the next global outbreak and taking steps to prevent future viruses from spilling over into human populations.
There are two competing arguments, that of a laboratory escape, or a spillover from animals.
Evidence shows that a laboratory escape is "highly unlikely", as a group of 21 scientists said in a paper published in Cell, a scientific journal, last month.
The paper, which reviewed scientific evidence over the origin of Sars-CoV-2 (the virus that causes Covid-19), said there was substantial evidence for a zoonotic origin, pointing out that the current pandemic bore clear similarities to the initial start of another coronavirus pandemic - Sars - which happened 17 years ago. Both were associated with wet markets selling live animals such as civets and raccoon dogs, known to be susceptible to infection by Sars-CoV-2.
As for claims that the coronavirus was engineered or worked on in a lab, the scientists pointed out that Sars-CoV-2 lacked mutations that would allow it to replicate easily in lab animals such as rats, which would likely be present if it was being studied in a lab setting.
"While the possibility of a laboratory accident cannot be entirely dismissed… this conduit for emergence is highly unlikely relative to the numerous and repeated human-animal contacts that occur routinely in the wildlife trade," said the paper.
However, the main argument for a lab escape seems to boil down to proximity - that the city in which Covid-19 first emerged happens also to be home to the Wuhan Institute of Virology (WIV), a laboratory that studies coronaviruses.
Apart from that, the scientists say, there is no solid evidence to suggest that early cases had links to the WIV, or that the institute was working on a progenitor virus.
There have been suggestions that the lack of evidence suggests a cover-up by the Chinese, but the reverse could also be true - that there could be no evidence for a lab accident simply because one never happened.
How the lab escape theory began
Talk of a lab origin for Covid-19 had begun under then US President Donald Trump when he suggested that it had leaked from the WIV.
"You could make the argument that when the Trump administration threw its support behind the lab-leak theory last year, it was politically motivated, to try and scapegoat China for his failure in handling the pandemic," said Dr Huang Yanzhong, a senior fellow for global health at the Council on Foreign Relations.
As a result, it was largely dismissed as a conspiracy theory under Mr Trump, but this changed when Mr Joe Biden took over this year.
In May, Mr Biden ordered his intelligence agencies to investigate the various theories, but the results of that 90-day investigation released last month were inconclusive.
Even so, and despite its claims that this inquiry should be guided by science and not politics, Chinese officials and state media have launched a coordinated social media campaign with posts in English and Chinese alleging that Covid-19 had been manufactured in Fort Detrick.
The base - once the centre of the US' biomedical weapons programme, and which now houses labs that conduct virus research - has come up repeatedly during the Chinese Foreign Ministry's daily press briefings in the past weeks.
"The US is blatantly applying double standards. On the one hand, it refuses to open the Fort Detrick base; on the other hand,
it demands an investigation into the lab in Wuhan," Foreign Ministry spokesman Wang Wenbin said last Tuesday.
China's fierce pushback shows how there is concern that Washington's accusations would undermine Beijing's official narrative of how it subdued the coronavirus.
"The message is essentially for domestic consumption - in that regard it has been very successful in convincing the domestic populace that the virus started in the US and likely from a military lab," said Dr Huang.
But this is a hard sell overseas, as WHO epidemiologist Michael Ryan said last month at a briefing: "It is slightly contradictory if colleagues in China are saying that the lab-leak hypothesis is unfounded in the context of China, but we now need to go and do laboratory investigations in other countries for leaks there."
Science mired in the sand
The result is that politics has left science stuck in the sand.
The international experts from the WHO say they need to go back to China and do further "trace-back studies" and surveys, including taking samples near wildlife farms that supplied markets in Wuhan, to figure out if there is any evidence of earlier spillover of the virus.
But China has blocked the WHO's proposal for this second phase of studies, which also includes audits of laboratories and markets in the city of Wuhan, on the basis of "political interference".
Professor Liang Wannian, who led the Chinese side of the WHO-convened investigation team to Wuhan earlier this year, told Chinese tabloid Global Times last week that the next phase of study should instead be carried out in "multiple countries and regions that registered early positive samples or cases".
Without China's approval, investigations have stalled, highlighting also how the WHO is ill-equipped to deal with China and the politics that has engulfed this pandemic.
"This is not helpful in any sense to the trust and coordination on a global problem, and combating things like vaccine hesitancy. All of it contributes to over-politicisation of this issue," said Mr Gregory Poling, senior fellow for South-east Asia at the Centre for Strategic and International Studies, a think-tank based in the United States.
But beyond the immediate scientific study, the issue has also turned regular Americans and Chinese against each other.
A Politico-Harvard poll in July showed that more than half of all Americans now believe that Covid-19 came from a Chinese lab.
Meanwhile, a survey of over 41,000 people by the Communist Youth League of China published last week showed over 98 per cent believed that the WHO should investigate Fort Detrick.
"When you have public opinions so polarised, the social foundation that supports a better US-China relationship will be seriously undermined. This is something that is really concerning," said Dr Huang.
There is also a danger that tensions could poison other important areas of cooperation - Chinese Foreign Minister Wang Yi in a video call with US climate envoy John Kerry this past week warned that souring ties could scupper US-China cooperation on matters related to climate change.
Beijing likes to frame its foreign policy as "win-win" and mutually beneficial, but politicising the virus is clearly anything but that.
Covid-19 has already killed more than 4.5 million people and sickened many millions more, yet the world is no closer to getting the answers and cooperation it needs to fight this pandemic and others that will no doubt come.