A diary took center stage in a contentious Senate hearing on Wednesday, offering a detailed look at the musings of Dr. Anthony Fauci, the scientist who became one of the most prominent voices in the U.S. response to the COVID-19 pandemic, and whose private reflections are now being used in an ongoing fight over how the pandemic began and how it was handled.

Sen. Rand Paul, a Kentucky Republican, has for years accused Fauci, the longtime top infectious disease official at the National Institutes of Health, of lying about the origins of the coronavirus. In earlier hearings, Fauci denied that accusation, calling it “preposterous.” On Wednesday, the retired doctor invoked the Fifth Amendment and declined to answer more questions.

Paul highlighted the latest hearing by releasing more than 1,000 pages of a diary Fauci kept over an extended period. Health Secretary Robert F. Kennedy Jr. told Fox News that his agency extracted the material from government computers and provided it to the GOP-led committee.

Using selected excerpts, Paul argued that Fauci’s “private record tells a different story” from the one he told the public.

Some of the entries had already been reflected in Fauci’s 2024 memoir and in interviews from that period, including the uncertainty he and other scientists faced while trying to understand a virus that had never been seen before and to determine how best to confront it. The diary now adds a more granular record of how that uncertainty played out inside government and in public-facing moments. Below are some takeaways from the diaries, with quotations edited to remove typos.

On January 26, 2020, Fauci wrote about whether early infections were tied to a market in China where animals were sold:

“It now appears using epi data and genomic data that the first infection was in early December and was not connected to the market. The infections spread among people weeks before the Chinese reported that they were dealing with a new infection and that gave the virus time to establish itself in multigenerational (sustained) spread. Remember, early on the Chinese were saying that there is no human to human transmission and all the original 27 cases were from the market. Now we know the market was not the source, it was the amplifier. Having said that, somewhere the virus jumped from animals to humans.”

A few weeks later, Fauci used almost the same language in a USA Today interview: “Almost certainly, somewhere, somehow a bat infected an intermediate host who infected a human. What epidemiologists feel is that the market was an amplifier of something that was already going on. So it didn’t necessarily start in the market, but when people congregated in the market they got infected from each other as opposed to all of them getting infected from whatever animal there was in the market.”

The comments came during the early scramble to determine the origins of the virus. In other diary entries, Fauci discussed convening government and non-government scientists who questioned whether the outbreak could have resulted from a lab leak, a theory Paul supports. The public debate over those competing explanations remains politically charged, even as the underlying scientific picture has continued to rely on incomplete evidence.

There is still no definitive proof, but many scientists believe the virus most likely emerged in nature and spread from animals to people, with the market serving as an early point of transmission. Fauci has long said he was open to both possibilities, while also saying the evidence more strongly supports COVID-19’s natural origins, as with its cousin SARS.

Fauci’s often rocky relationship with President Donald Trump, who initially praised him and later attacked him, also figures prominently in the diary. Fauci recorded both positive and negative moments in multiple entries, underscoring how the pandemic response was shaped not only by public health uncertainty but also by shifting White House politics and messaging.

On March 11, 2020, he wrote:

“We went in and presented to the POTUS and he asked good questions, many of them to me. He agreed and was clearly concerned more about the health of the American people than he was about the economy, which he said would recover.”

In an entry dated Aug. 4, 2020, Fauci described a White House meeting with Trump and other administration officials in which Trump was angry with several participants, including Fauci:

“He started raving that we are seeing more cases only because we are doing more testing,” Fauci wrote. He said he told the president, “Increased testing does not cause cases. When you increase testing you will of course pick up asymptomatics whom you might otherwise not notice. However, when you have increased percent positives and increased hospitalization, and increased deaths, that means that there are truly more cases.”

The diary also includes entries that move from daily events to Fauci’s growing media and celebrity attention, showing how the nation’s top infectious disease official became a familiar public figure far beyond the government briefings that defined the early pandemic.

On May 13, 2020, Fauci wrote about an Instagram discussion organized by the ONE Campaign with Julia Roberts:

“Had a wonderful Instagram discussion organized by the ONE Campaign with Julia Roberts. She was absolutely fabulous. She embarrassed me somewhat when I sat down in the chair and appeared on the screen through Zoom, she put her hands in front of her mouth and said ‘Oh my God. It’s Dr. Fauci, he is here.’ Then she went on to say that I was her personal hero and how happy she was to have this conversation with me. We discussed COVID-19 and its potential impact on the developing world. I told her that we have a moral responsibility to help and also we have enlightened self-interest in that if the outbreak continues in the developing world, it will always be a threat to the rest of the world. Also, we discussed the importance of including the developing world in the vaccine trials.”

Fauci also described a call from Trump’s then-Chief of Staff Mark Meadows while Trump was sick. The entry uses “sxs” for “symptoms” and includes details about Trump’s temperature, his oxygen level, which had dropped to worrying levels, and the decision to give the president an antiviral medication.

On October 4, 2020, Fauci wrote:

“Mark Meadows called my cell while I was walking on the C & O Canal at around 8:30 AM to ask my advice about when the POTUS could go out publicly again. I mentioned that the CDC guidelines say 10 days from the onset of sxs. His sxs started Thursday, Oct. 1 and so 10 days would be Saturday, Oct. 10. Mark told me that on Friday his temp was 103 and his O2 sat was in the 80s. That triggered the Remdesivir. Today (Sunday) he is up and about in his room and is afebrile. O2 sat is improved and he feels much better. I told Mark to send the POTUS my best wishes.”

This story was originally featured on Fortune.com