More than a decade after its outbreak, the name "SARS" still incites memories of worldwide panic over a disease that, we thought at the time, couldn't be stopped. Now, 13 years later, scientists have created a hybrid version of a virus that could be the world's next pandemic, a "SARS 2.0."

The findings have brought up ethical questions about whether scientists should pursue "gain-of-function" research, or work that could increase the virulence of certain pathogens, despite the dangers of creating a virus that could potentially wreak havoc if released into the wild.

Furthermore, the study comes in the wake of a US government announcement of a moratorium on federal funding for research that focused on the viruses that cause SARS (severe acute respiratory syndrome), as well as those that cause influenza and MERS. This study began before that ban was created, so it was grandfathered in and allowed to run to completion.

In order to study the virus in a lab, scientists created a "chimaeric virus," or a hybrid made of protein and the structure of a SARS virus. Critics say that the benefit isn't worth it to isolate a virus that, theoretically, could escape the lab and infect people.

"If the virus escaped, nobody could predict the trajectory," Simon Wain-Hobson, a virologist at the Pasteur Institute in Paris, told Nature.

The virus in question, a strain of bat coronavirus, is similar to severe acute respiratory syndrome (SARS), the disease that triggered widespread panic during an outbreak in Asia in 2002 and 2003 that spread to 29 countries, infected about 8,000, and killed over 700 people. After the outbreak, scientists concluded that the virus likely jumped from a species of bat to humans through a process called zoonotic transfer.

The findings could provide a way to create vaccines and immunotherapy treatments before the next epidemic strikes

Now, according to the new study published in the journal Nature Medicine, the very same bat species—the Chinese horseshoe bat—may be harboring another virus with similar characteristics. One of those characteristics is that, unfortunately for us, the "highly pathogenic" virus can be transferred to humans.

"The strain grew equally well to SARS in human cells," Dr. Ralph Baric, a professor of epidemiology at the University of North Carolina, Chapel Hill, and the lead author of the study, told Motherboard. "It resisted all vaccines and immunotherapy, too."

But Baric argues that the research is helpful to preparing vaccines for the next epidemic. Most often, one strain will emerge along with several other, very similar strains—just like these strains did among bat populations. Baric likens this to a swarm of emerging viruses.

"This is the main problem with emerging viruses," he said. "In animals, there is a beehive of emerging viruses. You get strains that are more and more diverse—but they're still closely related."

In this case, the newly-created virus, labeled SHC014-CoV, is just 12 percent different from SARS. And it's not if a strand like this will cause an outbreak—but when.

"We were actually fairly lucky with SARS; humanity was, I mean," said Baric. "It was a credit to public health actions, like quarantines—that's what really stopped [the] epidemic."

But, said Baric, if people hadn't acted quickly in the small window of 24 to 30 hours after it began, the SARS outbreak would have ended very differently.

"People don't realize how really lucky we are," he said.

According to Baric, the risk of "gain-of-function" research is worth it. The findings could provide a way to create vaccines and immunotherapy treatments before the next epidemic strikes. Because we have identified both SARS and SHC014-CoV, it's now possible to develop vaccines that could target those viruses and the viruses that share commonalities between them. In other words, the new findings may help develop vaccines for many more strains of infectious diseases even though we haven't identified them yet.

"Now, we can capture the entire swarm," Baric said. "That's the beauty of the study and most important take-home."