Fauci’s diary shows that Israeli data indicated waning COVID vaccine efficiency

Newly released records from Dr. Anthony Fauci’s personal diary suggest Israel played a far more influential role in shaping U.S. COVID-19 booster policy than was publicly understood, providing early evidence that vaccine protection was waning months before comparable American data emerged.

The documents, released on July 26 by Sen. Rand Paul (R-Ky.) ahead of Fauci’s appearance before the Senate Homeland Security and Governmental Affairs Committee, repeatedly cite Israeli studies, health officials and vaccination data as the Biden administration debated whether to recommend a third dose of the Pfizer-BioNTech vaccine. When Fauci later appeared before the committee on July 29, he declined to answer lawmakers’ questions, invoking his Fifth Amendment right against self-incrimination more than 100 times, leaving the diary as the most detailed public account of the administration’s internal deliberations.

Far from appearing only in passing, Israel features prominently throughout the more than 1,100 pages. The country is referenced dozens of times, reflecting how frequently American officials looked to Israeli data as they tried to understand the rapidly evolving pandemic.

Israel became the world’s COVID laboratory

By mid-2021, Israel occupied a unique position in the global fight against COVID-19. Having vaccinated much of its population months before most other countries, largely with the Pfizer-BioNTech vaccine, it became the first nation capable of measuring how vaccine protection changed over time in real-world conditions.

Its centralized healthcare system and comprehensive national health databases produced evidence that American officials simply did not yet possess.

Fauci’s diary repeatedly acknowledges that reality. Israeli officials, scientists and Health Ministry data became a critical reference point as Washington attempted to determine whether declining vaccine protection warranted an additional dose.

One of the diary’s earliest significant references appears on July 6, 2021, when Fauci recorded growing concern over new Israeli findings showing vaccine protection against infection had fallen sharply with the spread of the Delta variant—from roughly 94% before Delta to about 64%.

Although protection against severe illness remained high, the decline in protection against infection represented the first major indication that immunity might not remain as durable as hoped. Fauci summarized the findings by writing that there had been “a dramatic diminution with the delta variant in protection against infection and symptomatic disease.” He also noted, “We are starting to see an increase in hospitalizations, particularly in Israel in vaccinated people.”

Fauci considered the findings significant enough to brief President Joe Biden the same day.

Less than a week later, Pfizer executives presented similar Israeli data to senior U.S. health officials. Fauci noted that the company was reporting many of the same trends American officials had already learned from Israel.

Israeli evidence shaped the booster debate

As the summer progressed, Fauci’s diary records increasingly urgent concern over waning immunity.

By mid-August, he wrote that “the data clearly show that hospitalizations for people with two doses of vaccine are going up significantly particularly among the elderly and those with underlying conditions.” He also recorded that Israeli officials were reporting “a gradual waning of protection of the Pfizer vaccine over a few months,” with protection against infection and mild disease “dramatically diminished,” while protection against hospitalization had “also significantly decreased.”

The administration moved toward recommending booster shots even as American data remained incomplete. The diary records disagreement among prominent scientists, including vaccine expert Dr. Paul Offit and virologist Dr. Vincent Racaniello, who argued that broader evidence was still needed before recommending boosters for the general public.

Fauci repeatedly defended the administration’s position by pointing to Israeli experience.

Following discussions with Israeli health officials, including Health Ministry Director-General Professor Nachman Ash, public health chief Dr. Sharon Alroy-Preis and scientists from the Weizmann Institute of Science in Rehovot, Fauci concluded that Israel’s data justified moving ahead.

He described the Israeli findings as showing a gradual decline in vaccine protection over several months, followed by a significant restoration of protection after administration of a third dose.

“The Israelis have always been about a month or so ahead of the USA,” Fauci wrote after one such meeting.

Perhaps the diary’s clearest acknowledgment of Israel’s influence came when Fauci compared Israeli findings with the state of American evidence.

“The data from the U.S.A. cohorts was suggesting that but did not definitively show it,” he wrote after reviewing Israeli research.

Elsewhere, Fauci wrote, “These data are well ahead of the somewhat disjointed data from the CDC,” underscoring his view that Israeli observational evidence was outpacing the U.S. government’s own analysis.

The diary suggests Israeli observational studies helped fill a critical information gap while U.S. officials waited for their own data to mature. Summarizing the evidence, Fauci concluded: “It is clear from the Israel data that there is waning immunity across all of the age groups—not only for infection protection but also for protection against severe disease.”

The diary also describes unusually close communication between Fauci and Israel’s leadership. Fauci wrote that then-Prime Minister Naftali Bennett requested a Zoom meeting to seek his “opinion and ultimate support” for Israel’s booster campaign.

According to Fauci, Bennett recorded part of the discussion for Instagram and later asked for Fauci’s cellphone number so he could “intermittently call me for advice.” After obtaining State Department approval, Fauci wrote that he provided Bennett with his personal number.

Among the diary’s more revealing entries is Fauci’s discussion of the administration’s decision to recommend boosters eight months after the initial vaccination series.

Privately, Fauci wrote that the eight-month interval was not driven by biology or clinical evidence but largely by logistical considerations.

He also recorded frustration with White House officials who continued publicly describing the timeline as dictated by science.

“That is just not true,” Fauci wrote, arguing that officials should acknowledge that evolving Israeli evidence justified shortening the interval as additional data became available.

The entry offers a rare glimpse into the tension between scientific uncertainty, public messaging and policymaking during one of the pandemic’s most contentious periods.

Israel’s influence reached the White House

The diary also records the extent to which Israeli findings reached the highest levels of government.

Following one meeting with Israeli experts, Fauci wrote that “the people in the White House medical team are all excited now about the Israeli data” and said he wanted officials to appreciate “the extraordinary data that the Israelis have.”

During another conversation, Biden reportedly asked then-Israeli Prime Minister Naftali Bennett whether the United States was following Israel’s lead on booster shots. According to Fauci’s diary, “President Biden called me up on my cell phone. He said he was in with the Prime Minister of Israel and the Prime Minister was telling him that Israel will be giving their booster shot at five months.”

Fauci added: “The President wanted to know what we were doing about that and were we following the lead of Israel?”

The exchanges underscore the degree to which the Israeli experience had become a reference point for American decision-makers as they debated one of the most consequential public health policies of the pandemic.

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