WASHINGTON — The former director of the Centers for Disease Control and Prevention accused top federal health officials on Wednesday of excluding him from discussions in early 2020 about whether the coronavirus was the result of a laboratory leak — an assertion that one of the officials, Dr. Anthony S. Fauci, later said had “nothing to do with reality.”
Three years into the pandemic, the accusation by the former C.D.C. director, Dr. Robert R. Redfield, put a spotlight on the lingering bitterness and partisan divisions around the scientific question of the virus’s origins.
Dr. Redfield, a virologist who ran the C.D.C. during the Trump administration, believes the pandemic was most likely the result of a lab leak. He testified on Wednesday at the first hearing of the House Select Subcommittee on the Coronavirus Pandemic, which is digging into the origins of a virus that has killed nearly seven million people worldwide.
The hearing produced no new evidence but plenty of political theater, and it made clear just how difficult it might be to turn up conclusive evidence about whether the virus escaped from a lab or spilled over from animals to humans naturally. It is a question worth answering, said Representative Ami Bera, Democrat of California, a doctor who serves on the subcommittee and said he was agnostic on the issue.
“Assigning blame is not going to bring back seven million people,” Mr. Bera said in an interview. “But it might prevent another seven million deaths, if we understand what happened.”
Dr. Redfield said the answer would probably come from intelligence agencies, not scientists, and lawmakers of both parties seem to agree. Last week, the Senate passed a bill ordering the declassification of intelligence related to the Wuhan Institute of Virology, a laboratory that specializes in coronavirus research in Wuhan, China, where the pandemic began. The House is expected to take up the measure on Friday.
On the other side of the Capitol complex, the director of national intelligence, Avril D. Haines, told the Senate Intelligence Committee on Wednesday that there was a consensus that the virus that causes Covid-19 was not engineered as a biological weapon, but that intelligence agencies disagreed on whether it leaked from a lab or came from natural exposure to an infected animal. China has destroyed evidence, complicating the search for the cause.
“We’ve been trying to collect additional information, and I think you’re absolutely right that China has not fully cooperated,” Ms. Haines said, responding to a question from Senator Marco Rubio, Republican of Florida and the committee’s vice chairman. “And we do think that’s a key critical gap that would help us to understand what exactly happened.”
In the United States, the notion that the coronavirus emerged from a lab was initially dismissed as a conspiracy theory by critics of President Donald J. Trump, who embraced the idea while trying to blame China for the pandemic. But it is now getting a second look, in part because new intelligence has led the Energy Department to conclude, with low confidence, that the pandemic was most likely the result of a lab accident.
“There is no smoking gun proving a laboratory origin hypothesis, but the growing body of circumstantial evidence suggests a gun that is at very least warm to the touch,” said another witness at the House hearing, Jamie Metzl, a senior fellow at the Atlantic Council who worked in the Clinton administration and described himself as a Democrat.
In making the case for a laboratory leak, multiple witnesses focused on a particular feature of the virus that causes Covid-19. That feature, called a furin cleavage site, helps the virus efficiently infect human cells.
In 2018, EcoHealth Alliance, a research nonprofit, and several of its partners, including the Wuhan Institute of Virology, sought funding from the Defense Department to experiment on coronaviruses that could spread in humans. Their proposal, which was rejected, involved studying furin cleavage sites.
One of the witnesses, Nicholas Wade, who served as The New York Times’s science editor in the 1990s and left the news organization at the end of 2011, told lawmakers that researchers may have already done experiments in which they inserted furin sites into coronaviruses.
Mr. Wade questioned the likelihood that evolution would “produce, at that very time and at that very place, a virus of the exact type described” in the groups’ proposal.
EcoHealth said on Wednesday that researchers did not do the experiments before proposing them in part because they “required a substantial budget.”
No evidence has yet emerged showing that the Wuhan lab’s researchers had any virus in its collections that could have been altered to make the virus that causes Covid-19. Scientists have said natural evolutionary processes could easily explain the presence of the furin cleavage site.
While close known relatives of the coronavirus that emerged in Wuhan are missing a furin cleavage site, many other coronaviruses have that same signature feature, including coronaviruses that cause colds.
Dr. Redfield testified that he was alarmed by the furin cleavage site, which, he said, “totally changes the orientation now so it has high affinity for human receptors,” transforming its ability to bind to human cells.
But coronaviruses, including bat coronaviruses discovered in Laos in 2020, can latch onto human cells without a furin cleavage site. Stephen Goldstein, a virologist at the University of Utah, said the furin site affected the virus’s route of entry into cells, but not its binding ability.
“Everything he said was wrong,” Dr. Goldstein said of Dr. Redfield. “Robert Redfield is either ignorant or lying to Congress.”
Dr. Redfield’s accusation that he was excluded from discussions over the virus’s origins revolves around email exchanges and a phone conversation in early February 2020 — a month before the World Health Organization declared a pandemic — in the rush to figure out where the new virus had come from.
At the time, some scientists said the furin cleavage site made them wonder whether the virus had been engineered. The emails show that Dr. Jeremy Farrar, a British medical researcher, set up a call so scientists could discuss it. Dr. Fauci, at the time the director of the National Institute of Allergy and Infectious Diseases, and Dr. Francis S. Collins, who led the National Institutes of Health, were on the call.
Dr. Redfield said he did not find out about the call until much later, when the emails became public. The messages do not refer to or name Dr. Redfield. But he told lawmakers that when he learned of them, he concluded that Dr. Fauci and Dr. Collins had intentionally excluded him because he believed the virus had originated in a lab.
“It was told to me that they wanted a single narrative and that I obviously had a different point of view,” Dr. Redfield said. He did not specify who made that remark, and he declined to answer questions after the hearing.
But in an interview, Dr. Fauci said he and Dr. Collins did not organize the call, which brought together evolutionary biologists, including some who suspected that the virus had been made in a lab. He also said he did not know what Dr. Redfield’s views were at the time.
“It doesn’t make any sense that he was excluded because he had a different opinion,” Dr. Fauci said. “Half the people on the call felt that way.”
A few days after that call, the scientists who had suspected a lab leak changed their assessments, as they had initially said might happen. After doing further investigation, they concluded that the genetic evidence was inconsistent with a virus that had been deliberately engineered, and they later published a study laying out their research.
If there was a single point of agreement at Wednesday’s hearing, it was that politicians should put partisanship aside so that an unbiased inquiry could proceed. But lawmakers did not always practice what they preached.
Democrats used some of their time to attack Mr. Trump and assail Mr. Wade, who wrote a 2014 book, “A Troublesome Inheritance,” that argued there is a biological basis for race. Representative Raul Ruiz of California, the subcommittee’s top Democrat, called Mr. Wade’s ideas “discredited, unscientific and harmful.” Mr. Wade countered that his book was “explicitly antiracist,” adding, “I stress the fact that we are all variations on the same human genome.”
Republicans, in turn, repeatedly attacked Dr. Fauci, who has become a frequent target for the party. That prompted a warning from Mr. Metzl, who cautioned lawmakers against focusing on Dr. Fauci as they search for the pandemic’s origins.
“If we make it primarily about Dr. Fauci,” he said, “we will be inappropriately serving the Chinese government a propaganda coup on a silver platter. ”
Julian E. Barnes contributed reporting.