More than a year after then US president Donald Trump alleged that COVID-19 could have been engineered in a lab, the Wuhan Institute of Virology is facing renewed scrutiny over the origin of the pandemic.
Over the past two weeks, media reports and US officials have spoken about reinvestigating the possibility of whether COVID-19 was man-made.
On Sunday, the UK's Daily Mail published details of a study by a British professor and a Norwegian scientist that suggests Chinese scientists created the virus while conducting a controversial experiment.
British professor Angus Dalgleish is a professor of oncology at St George's University in London, who has worked on HIV vaccine research. Norwegian scientist Dr Birger Sorensen is a virologist who is chair of Immunor, a pharmaceutical company that has developed a COVID-19 vaccine candidate, Biovacc-19.
The duo have submitted their study for publication in the Quarterly Review of Biophysics Discovery. Dalgleish and Sorensen claimed the study concludes COVID-19 has "no credible natural ancestor" and it was "beyond reasonable doubt" that the virus was created through "laboratory manipulation".
Dalgleish and Sorensen claim their work was a forensic analysis of experiments done at the Wuhan lab between 2002 and 2019.
Dalgleish and Sorensen focused on 'Gain of Function' research at the lab. According to the Daily Mail, "Gain of Function involves tweaking naturally occurring viruses to make them more infectious, so that they can replicate in human cells in a lab, allowing the virus's potential effect on humans to be studied..." Gain of Function research was outlawed in the US by the Barack Obama administration.
Dalgleish and Sorensen said Chinese scientists took a natural coronavirus 'backbone' found in Chinese bat caves and engineered a new spike in it to create what is now COVID-19.
To substantiate their claims of modification in a lab, they pointed to the presence of a row of four amino acids on a SARS-Cov-2 spike they examined.
Sorensen told The Daily Mail, "the amino acids all have a positive charge, which cause the virus to tightly cling to the negatively charged parts of human cells like a magnet, and so become more infectious. But because, like magnets, the positively charged amino acids repel each other, it is rare to find even three in a row in naturally occurring organisms, while four in a row is 'extremely unlikely'".
"The laws of physics mean that you cannot have four positively charged amino acids in a row. The only way you can get this is if you artificially manufacture it," Dalgleish told Daily Mail.
"A natural virus pandemic would be expected to mutate gradually and become more infectious but less pathogenic, which is what many expected with the COVID-19 pandemic but which does not appear to have happened,” Dalgleish and Sorensen wrote.
Making it natural
Another explosive claim made by Sorensen and Dalgleish in their study is that they believe
Chinese scientists took samples of COVID-19 after the pandemic began last year and "retro-engineered" it to make it appear to have been naturally occurring.
"They said they were suspicious of a raft of new strains suddenly entered into gene databases by predominantly Chinese scientists early in 2020, years after they were recorded as being collected," Daily Mail reported.
"It appears that preserved virus material and related information have been destroyed. Therefore we are confronted with large gaps in data which may never be filled. Strains 'popped up' after January 2020 are not credible... For a year, we have possessed prima facie evidence of retro-engineering in China in early 2020," the researchers were quoted as saying by Daily Mail.
They alleged there was "deliberate destruction, concealment or contamination of data" by Chinese labs and even Chinese scientists who wished to share information "disappeared".
UK experts had initially dismissed claims
Dalgleish and Sorensen had propounded the theory COVID-19 was engineered in a lab an year ago, but their claims were dismissed as fake. Dr Rachael Tarlinton, an associate professor of veterinary virology at the UK University of Nottingham, told Sky News in July 2020 their theory was "magical thinking".
"Professor Kristian Andersen, of the department of immunology and microbiology at Scripps research facility in California, described Dalgleish and Sorensen's first paper last summer as "complete nonsense, unintelligible, and not even remotely scientific", Daily Mail reported.