Tucked away in the more than 4,000-page omnibus spending bill passed by the Senate on Thursday is a provision that sets new guardrails against risky viral research that some scientists and lawmakers believe could have played a role in the origins of the COVID-19 pandemic.

Within the $1.7 trillion legislation, which will add to the $31 trillion national debt, lawmakers defunded certain National Institutes of Health grants for research experiments involving "pathogens of pandemic potential" conducted in foreign countries "of concern." 

The language was added after several GOP senators called on the Biden administration to pause all federally funded gain-of-function research they say may have been responsible for the outbreak of the SARS-CoV-2 virus that causes COVID-19. 

"Beginning not later than 60 days after the date of the enactment of this ACT, the Secretary of Health and Human Services shall not fund research conducted by a foreign entity at a facility located in a country of concern … involving pathogens of pandemic potential or biological agents or toxins," page 3,354 of the omnibus bill states. 

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Peter Daszak and Thea Fischer, members of the World Health Organization (WHO) team tasked with investigating the origins of the coronavirus disease (COVID-19), sit in a car arriving at Wuhan Institute of Virology in Wuhan, Hubei province, China February 3, 2021. REUTERS/Thomas Peter

Members of the World Health Organization team tasked with investigating the origins of the coronavirus disease visit the Wuhan Institute of Virology in Wuhan, China.  (REUTERS/Thomas Peter)

Sen. Roger Marshall, R-Kan., one of the Senate Republicans leading the charge for greater oversight of gain-of-function research, called the measure a good "first step." 

"While I am pleased that these new guardrails will help prevent American taxpayer dollars from funding risky research in foreign countries of concern, this is just the first step, and we must do more," Marshall told Fox News. 

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"We need to close policy loopholes by restricting all federal agency funding for risky research, including sub-awards, to every country determined to be countries of concern and/or in violation of the bioweapons convention act treaty. 

"No U.S. tax dollars should fund risky research in China. Period," he emphasized.  

United States Senator Roger Marshall

U.S. Sen. Roger Marshall, R-Kan., speaks at a press conference at the U.S. Capitol Aug. 5, 2022, in Washington, D.C.  (Kevin Dietsch/Getty Images)

Gain-of-function research is a controversial area of experimentation that can include engineering viruses and pathogens to be more transmissible, or even deadlier, to study how diseases might evolve and develop potential treatments or vaccines. 

The Obama administration paused new funding for gain-of-function research in 2014 to "assess the potential risks and benefits." However, it was reinstated by the National Institutes of Health (NIH) in 2017, and Marshall and other Republicans have argued new barriers to this research are needed after evidence suggested the Wuhan Institute of Virology in Wuhan, China, was conducting gain-of-function research experiments before the outbreak of COVID-19. 

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The NIH funded gain-of-function research at the Chinese lab, according to government documents obtained by The Intercept. The story countered claims from Dr. Anthony Fauci, the outgoing head of the National Institute of Allergy and Infectious Diseases (NIAID), and Dr. Francis Collins, who was the head of NIH at the start of the pandemic. 

Medical experts noted that this NIH-funded gain-of-function research in Wuhan, where the virus first spread, could not have directly caused the COVID-19 outbreak but suggest the lab may have lacked proper oversight and engaged in risky research.

The EcoHealth Alliance logo

In this photo illustration from May 3, 2020, an EcoHealth Alliance logo is displayed on a smartphone.  ( Igor Golovniov/SOPA Images/LightRocket )

NIH admitted last year that the organization it funded for research in Wuhan, EcoHealth Alliance, failed to immediately report an "unexpected result" from its research in 2018 and 2019 that created a coronavirus that was more infectious in mice. The agency terminated the grants to Wuhan in August after a two-year investigation. Previous government-funded studies in Wuhan included funds from Fauci’s NIAID on bat coronavirus research.

The White Coat Waste Project, a watchdog group that advocates against animal experimentation and exposed taxpayer-funded gain-of-function research at the Wuhan lab, lauded lawmakers for cracking down on "supercharging dangerous viruses in foreign enemies' animal labs." 

"A majority of Americans — Democrats, Republicans and independents alike — support these commonsense measures to crack down on wasteful government spending that hurts animals and taxpayers, and we applaud lawmakers for taking action," said Justin Goodman, senior vice president, advocacy and public policy, at White Coat Waste Project.

The origin of COVID-19 is still unknown. Republican-led investigations in both the House and Senate concluded that a lab leak is the most likely origin. The World Health Organization, backed by most prominent science organizations, asserts the most likely origin is a natural jump from animals to people.

 Fox News' Patrick Hauf contributed to this report.