What we know: US intelligence found Wuhan lab researchers fell sick in fall 2019

WASHINGTON — A U.S. intelligence report found that three researchers at a lab in Wuhan, China, the city where the coronavirus pandemic is believed to have originated, fell sick in the fall of 2019, according to new reports.

The finding, first reported by the Wall Street Journal, has prompted questions into the origins of COVID-19. U.S. officials and scientists have long said not enough is known to determine definitively whether the virus jumped from animals to humans or came out of a laboratory.

Here's what we know about the new report: 

What do we know about where the coronavirus came from?

Early theories were that the virus that causes COVID-19 jumped directly from animals to humans, because that is how over 70% of new human infections began in recent decades. One possible explanation is that the virus jumped from bats to humans, or first to another animal before spreading to humans. The earliest cases of COVID-19 infection were traced back to a wildlife market in Wuhan.

Prep for the polls: See who is running for president and compare where they stand on key issues in our Voter Guide

COVID-19 is caused by a virus called SARS-CoV-2, which belongs to the coronavirus family of viruses. Research published last summer in the journal Nature suggested the virus first evolved in bats and circulated among them for decades before jumping to people, possibly after passing through another animal first.

Another possibility: The virus accidentally escaped from a lab where it was being studied, collected from a bat or other animal.

The World Health Organization stated earlier this year that there was not enough evidence to suggest that the lab theory held merit. 

A team from the World Health Organization that spent two weeks in China earlier this year was not allowed full access to labs studying similar viruses and data about early coronavirus cases, and scientists have called for open, transparent access to such information.

The lab theory first emerged from a series of sources with circumstantial evidence, including repeated assertions from former President Donald Trump and his allies, without citing specific evidence. Other speculation was based on the proximity of the Wuhan Institute of Virology to the wildlife market where the first cases of the coronavirus were traced in Wuhan, and China's initial unwillingness to share information about the virus.

Scientists have said that the lack of information has fed conspiracy theories, and partisan back-and-forth over the issue and over the U.S.' support for the World Health Organization has turned the source of the virus into a political flashpoint. 

Scientists have determined that the virus is not manmade, meaning that if it did accidentally escape from a laboratory, it still would have originated from nature.

What's in the U.S. intel report?

The report claims that three Wuhan Institute of Virology employees were hospitalized with possible coronavirus symptoms in November 2019, according to the Wall Street Journal. The report added new information on the details of the timing that the employees were hospitalized, a month before China reported its first infections. 

The U.S. previously confirmed that employees at the institute had fallen ill with symptoms consistent with COVID-19 "and common seasonal illness" last fall, according to the State Department during the last days of the Trump administration, but the new report adds that the employees sought treatment in the hospital and that the illness predates China's first reported infections.

According to Chinese data as reported to the World Health Organization, the first COVID cases were identified in December 2019.

"This raises questions about the credibility of WIV senior researcher Shi Zhengli’s public claim that there was 'zero infection' among the WIV’s staff and students of SARS-CoV-2 or SARS-related viruses," the January 2021 fact sheet from the State Department reads.

Animals or a lab?:Top American scientists join call for answers on coronavirus origin.

The report is not conclusive evidence that the coronavirus escaped from a lab, and the intelligence community still does not know for sure what the researchers were sick with, CNN reported.

How are leaders responding to the report?

China denied the new report on Monday. China's leaders, along with the World Health Organizations, have sought to downplay calls for an investigation into whether the virus could have escaped from the laboratory for months. 

White House Press Secretary Jen Psaki, asked about the controversy Monday, said the administration has been pressing for an international investigation led by the World Health Organization.

"We need that data. We need that information from the Chinese government," she said. "What we can't do, and what I would caution anyone doing, is leaping ahead of an actual international process."

Yuan Zhiming, director of the lab, told the Global Times the Journal report was "groundless." China's foreign ministry spokesman, Zhao Lijian, also called the claim "completely untrue."

"The U.S. continues to hype the lab leak theory. Is the real intention to express concern over the virus origin or to divert attention?" Zhao asked

Some Republicans, including Rep. Matt Gaetz, R-Fla., said the WHO cannot be trusted to conduct an independent investigation. The Trump administration previously revoked U.S. funding for the organization, accusing it of being too partial to Chinese interests, but Biden reinstated funding when he came into office earlier this year. 

Contributing: Karen Weintraub, Maureen Groppe, Kim Hjelmgaard