The chief scientist for emerging disease at the Wuhan Institute of Virology, "Bat Lady" Dr Shi Zhengli has rejected fresh claims Covid-19 may have escaped from her lab as "sad" and "not acceptable".
A group of 18 scientists including one of the world's foremost coronavirus researchers has reignited the debate over whether Covid-19 escaped from a Wuhan lab.
Warning there was not enough evidence to rule the option out, the group wrote to the prestigious Science magazine urging further investigation into the origins of the Covid-19 strain responsible for the global pandemic.
"We must take hypotheses about both natural and laboratory spillovers seriously until we have sufficient data," the letter states.
"A proper investigation should be transparent, objective, data-driven, inclusive of broad expertise, subject to independent oversight, and responsibly managed to minimise the impact of conflicts of interest.
"Public health agencies and research laboratories alike need to open their records to the public. Investigators should document the veracity and provenance of data from which analyses are conducted and conclusions drawn, so that analyses are reproducible by independent experts."
The signatories include respected scientists who are experts in SARS-CoV-2 research, including Jesse Bloom, a computational biologist at the Fred Hutchinson Cancer Research Center in Seattle; Ralph Baric, a coronavirus researcher who has collaborated with scientists at the Wuhan Institute of Virology in China and David Relman, a microbiologist and immunologist at Stanford University School of Medicine.
But Wuhan virologist Shi Zhengli, has hit back in an email to MIT Technology Review on Friday morning over calls for her to hand over her lab records.
"It's definitely not acceptable," Shi said. "Who can provide an evidence that does not exist?"
"It's really sad to read this 'Letter' written by these 18 prominent scientists.
"The hypothesis of a lab leaking is just based on the expertise of a lab which has long been working on bat coronaviruses which are phylogenetically related to SARS-CoV-2.
"This kind of claim will definitely damage the reputation and enthusiasm of scientists who are dedicated to work on the novel animal viruses which have potential spillover risk to human populations and eventually weaken the ability of humans to prevent the next pandemic."
The scientists' letter does note the debate has the capacity to fuel anti-China sentiment.
"Finally, in this time of unfortunate anti-Asian sentiment in some countries, we note that at the beginning of the pandemic, it was Chinese doctors, scientists, journalists, and citizens who shared with the world crucial information about the spread of the virus - often at great personal cost," the letter to Science states.
"We should show the same determination in promoting a dispassionate science-based discourse on this difficult but important issue."
A team of scientists sent to Wuhan, China, by the World Health Organisation to investigate the origins of Covid-19 have previously dismissed the hypothesis as "extremely unlikely".
Peter Ben Embarek, a Danish food safety and animal disease specialist who chaired the investigation team said: "It isn't a hypothesis we suggest implies further study."
"Accidents do happen," he said but he maintained the viruses kept in the Wuhan laboratory were genetically different from the SARS-CoV-2 virus.
But the letter to Science magazine said the WHO investigation was too quick to discount the theories.
"In May 2020, the World Health Assembly requested that the World Health Organisation (WHO) director-general work closely with partners to determine the origins of SARS-CoV-2 (2),'' the letter states.
"In November, the Terms of Reference for a China–WHO joint study were released. The information, data, and samples for the study's first phase were collected and summarised by the Chinese half of the team; the rest of the team built on this analysis.
"Although there were no findings in clear support of either a natural spillover or a lab accident, the team assessed a zoonotic spillover from an intermediate host as 'likely to very likely', and a laboratory incident as 'extremely unlikely'.
"Furthermore, the two theories were not given balanced consideration. Only 4 of the 313 pages of the report and its annexes addressed the possibility of a laboratory accident.
"Notably, WHO Director-General Tedros Ghebreyesus commented that the report's consideration of evidence supporting a laboratory accident was insufficient and offered to provide additional resources to fully evaluate the possibility.
"As scientists with relevant expertise, we agree with the WHO director-general, the United States and 13 other countries and the European Union that greater clarity about the origins of this pandemic is necessary and feasible to achieve."
Scientists who co-signed the letter have called for concerns the virus escaped from a lab to be the subject of more investigation and urged caution over the WHO report's premature dismissal of the lab leak theory.
"Show us the test you used: What was the method? What were the results and the names of the people tested? Did you test a control population?" Dr David Relman, a professor of microbiology and immunology at Stanford University told the Los Angeles Times.
"On all accounts, it was not an adequate, detailed kind of presentation of data that would allow an outside scientist to arrive at an independent conclusion.
"We're reasonable scientists with expertise in relevant areas," Relman said, "and we don't see the data that says this must be of natural origin."
WHO chief's comments on origins of the virus
Even Tedros Adhanom Ghebreyesus, the director general of the WHO, has previously expressed concern the lab theory should not be dismissed.
"Although the team has concluded that a laboratory leak is the least likely hypothesis, this requires further investigation, potentially with additional missions involving specialist experts, which I am ready to deploy," he said in an address to WHO member states on March 30.
"Let me say clearly that, as far as WHO is concerned, all hypotheses remain on the table."
Recently, the former New York Times and Science reporter Nicholas Wade published a 10,000-word article raising the possibility that Covid-19 was a human-engineered pathogen and that it had escaped.
He also accused the US National Institute of Allergy and Infectious Diseases (NIAID) of funding gain-of-function (GoF) research at the Wuhan Institute of Virology.
But questioned over the claims in a US Senate hearing top US infectious diseases expert Anthony Fauci rejected the claim when questioned by Senator Rand Paul.
"Senator Paul, with all due respect, you are entirely, entirely and completely incorrect. The NIH has not ever, and does not now, fund 'gain of function research' in the Wuhan Institute,'' Dr Fauci said.
He insisted the NIH gave a grant to EcoHealth Alliance, "a non-profit focused on research that aims to prevent pandemics", which then passed a part of it to the Wuhan Institute – but it was not intended for gain of function research.