Coronavirus: COVID-19 pandemic possibly 70 years in the making - study

It's new to science, but the virus which causes COVID-19 might have been biding its time since before the reign of Queen Elizabeth II began.

And researchers say there could be others like it still waiting to make the jump from bat to human. 

SARS-CoV-2 was first detected late last year in Wuhan, China, when dozens of people came down with a mysterious respiratory illness that didn't respond to conventional treatment. Since then COVID-19, as the illness was later dubbed, has killed 670,000 people.

Suspicion immediately fell on bats, which have incredibly strong immune systems which encourage viruses to evolve quickly. 

"While the bats can tolerate viruses like these, when these bat viruses then move into animals that lack a fast-response immune system, the viruses quickly overwhelm their new hosts, leading to high fatality rates," scientists from the University of California, Berkeley said in February, early in the international outbreak.

Parts of SARS-CoV-2 also resemble a virus found in pangolins, which like bats are sold at wet markets in Wuhan and across Asia. Viruses are able to swap genetic material in a process called recombination, leading some to believe the virus jumped to pangolins and acquired some new traits, giving them the ability to infect humans.

In a new study scientists from Pennsylvania State University say it's unlikely pangolins are involved, with SARS-CoV-2 possibly diverging from pangolin and other bat viruses more than 70 years ago.

"The authors removed regions of the bat, human and pangolin coronavirus sequences that are thought to exchange information with each other when they are found in the same host," said Mark Pagel, a professor of evolutionary biology at the University of Reading. 

"Previous studies have not done this.  Removing these regions leaves a clearer signal of ancestry and improves dating."

What they found was SARS-CoV-2 and its most closely-related known bat virus RaTG13 share a common ancestor with the pangolin virus, but diverged possibly as early as 1948 - the same year Prince Charles, Ozzy Osbourne and Alice Cooper were born. Two other analyses suggested dates of 1969 - the same year as the moon landing - and 1982, when Prime Minister Jacinda Ardern was just two years old. 

The spike protein on SARS-CoV-2, which resembled that in the pangolin virus, showed no signs of recombination - suggesting pangolins have been unfairly maligned. 

Prof Pagel, who was not involved in the study, said if the findings are correct there will likely be other coronaviruses we'll have to be on the lookout for. 

"There will be coronaviruses circulating in horseshoe or other closely related bats that will prove to be closer to COVID-19 than is RaTG13.  In an earlier epidemic - that of the original SARS - researchers searched for over 14 years before finding the probable source, also in horseshoe bats."

The Pennsylvania State University team said that will be difficult, with viruses evolving so quickly. 

"Existing diversity and the dynamic process of recombination amongst lineages in the bat reservoir demonstrate how difficult it will be to identify viruses with the potential to cause significant human outbreaks before they emerge, underscoring the need for real-time human disease surveillance systems that can rapidly identify and classify pathogens."

The research was published this week in journal Nature Microbiology. Unlike much other research into COVID-19, the study has been peer-reviewed. researchers say there could be others like it still waiting to make the jump from bat to human.