Over two days of questioning during his Senate confirmation hearings last year, Robert F Kennedy Jr repeated the same answer.

He said the closely scrutinized trip he took to Samoa in 2019, which came ahead of a devastating measles outbreak, had “nothing to do with vaccines”.

Documents obtained by the Guardian and the Associated Press undermine that testimony. Emails sent by staff at the US embassy and the United Nations provide, for the first time, an inside look at how Kennedy’s trip came about and include contemporaneous accounts suggesting his concerns about vaccine safety motivated the visit.

The documents have prompted concerns from at least one US senator that the lawyer and activist now leading America’s health policy lied to Congress over the visit. Samoan officials later said Kennedy’s trip bolstered the credibility of anti-vaccine activists ahead of the measles outbreak that sickened thousands and killed 83 people, mostly children under age five.

The revelations, which come as measles outbreaks erupt across the US, build on previous criticism that Kennedy’s anti-vaccine record makes him unfit to serve as health secretary, a role in which he has worked to radically reshape immunization policy and public perceptions of vaccines.

The newly disclosed documents also reveal previously unknown details of the trip, including that a US embassy employee helped Kennedy’s team connect with Samoan officials. Kennedy, then running his anti-vaccine group Children’s Health Defense, did not publicly discuss the trip at the time, but has since said his “purpose” for going there was not related to vaccines and that “I ended up having conversations with people, some of whom I never intended to meet.”

In addition to meeting with anti-vaccine activists, Kennedy met with Samoan officials, including the health minister at the time, who told NBC News that Kennedy shared his view that vaccines were not safe. Kennedy has said he went there to introduce a medical data system.

The US Department of State turned over the emails – many of which are heavily redacted – as a result of an open records lawsuit brought with the assistance of the Reporters Committee for Freedom of the Press.

These disclosures come at a time when Kennedy, as Donald Trump’s health secretary, has used his power and enormous public influence to overhaul federal immunization guidance and raise suspicion about the safety and importance of vaccines, including the measles vaccine. Meanwhile, measles outbreaks in multiple US states have rolled back decades of success in eliminating the highly contagious disease, putting the country on the verge of losing its elimination status. The latest figures show over 875 people in South Carolina have been infected.

Kennedy addressed questions about his trip to Samoa during two Senate confirmation hearings for his appointment as health secretary.

“My purpose in going down there had nothing to do with vaccines,” he said under questioning by Senator Edward Markey of Massachusetts in his 30 January 2025 hearing.

“Did the trip have nothing to do with vaccines as you told my colleagues in Senate finance yesterday?” Markey asked later.

“Nothing to do with vaccines,” Kennedy replied.

One of the senators who questioned Kennedy about Samoa during his confirmation hearings, Senator Ron Wyden, a Democrat from Oregon, responded to the new records by saying “Kennedy’s anti-vaccine agenda is directly responsible for the deaths of innocent children.”

“Lying to Congress about his role in the deadly measles outbreak in Samoa only underscores the danger he now poses to families across America,” Wyden said in an email. “He and his allies will be held responsible.”

Taylor Harvey, a spokesman for Wyden and other Democrats on the Senate finance committee, said it is a crime to make a false statement to Congress and “casual, false denials to Congress will not be swept under the rug”.

A spokesman for the US Department of Health and Human Services did not respond to questions sent by email and text message.

Kennedy has said his visit did not influence people’s decisions on whether to get themselves or their children immunized.

“I had nothing to do with people not vaccinating in Samoa. I never told anybody not to vaccinate,” he told the 2023 documentary Shot in the Arm. “I didn’t, you know, go there for any reason to do with that.”

Anti-vaccine activists in the United States became interested in Samoa in July 2018, when two babies died after being injected with a tainted measles, mumps and rubella vaccine that had been improperly prepared. The government halted the vaccine program for 10 months, until the following April. Vaccination rates plummeted.

The new records show that during the time when no vaccines were being administered, Kennedy’s group, Children’s Health Defense, was trying to connect Kennedy with Samoa’s prime minister. A January 2019 email from the group’s then-president, Lyn Redwood, to Samoan activist Edwin Tamasese, asked him to “please share this letter with the Honorable Prime Minister Tuilaepa Aiono Sailele Malielegaoi for Robert Kennedy, Jr.”

About two months later, Tamasese wrote back to Redwood, with a cc: to Kennedy and others.

“Hope all is well, organizing logistics with the PMs office and wanted to confirm how many people are coming? Also just wanted to confirm costs etc for the visit and how this will be handled,” he wrote.

Tamasese immediately forwarded the chain of messages to both the personal and government email accounts of Benjamin Harding, at the time an employee of the US embassy in Apia, Samoa.

“just sent this. expecting an answer tomorrow as I think it is Sunday there. your letter looks good,” Tamasese told Harding.

While the US embassy in the past has acknowledged that an unnamed staffer attended an event with Kennedy and anti-vaccine activists while he was in Samoa, the new records show that Harding wasn’t a passive attendee: he helped arrange Kennedy’s visit and connected Kennedy’s delegation with Samoan government officials.

In a 23 May 2019 email to Harding’s personal email address, a staffer for the Samoan ministry of foreign affairs and trade wrote: “Hi Benj, Currently awaiting the official bio-notes for Mr Kennedy and Dr Graven to convey to the Hon. Prime Minister and Hon. Minister of Health for their reference. Please note, that this needs to be sent with our official letter when requesting an appointment.”

Harding forwarded the ministry’s request to Dr Michael Graven, then the chief information officer at Children’s Health Defense.

Harding did not respond to messages seeking comment sent to several listed email addresses, social media accounts, a phone number listed to his parents and a general mailbox at a company he lists as a current workplace on his LinkedIn profile.

Embassy staff got a tip about Harding’s involvement in the trip from Sheldon Yett, then the representative for Pacific island countries at Unicef, the United Nations Children’s Fund.

“We now understand that the Prime Minister has invited Robert Kennedy and his team to come to Samoa to investigate the safety of the vaccine,” Yett wrote in a 22 May 2019 email to an embassy staffer based in New Zealand. “The staff member in question seems to have had a role in facilitating this.”

Two days later, a top embassy staff member in Apia wrote to Scott Brown, then Trump’s US ambassador to New Zealand and Samoa, alerting him to Kennedy’s trip and Harding’s involvement.

“The real reason Kennedy is coming is to raise awareness about vaccinations, more specifically some of the health concerns associated with vaccinating (from his point of view),” the embassy official, Antone Greubel, wrote. “It turns out our very own Benjamin Harding played some role in a personal capacity to bring him here.” Greubel wrote that he told Harding to “cease and desist from any further involvement with this travel,” though the rest of the sentence is redacted.

Yett did not respond to questions, though said in an email, “that was a very grim time in Samoa.”

Brown, who is running for Senate in New Hampshire, declined to comment. Greubel referred questions to a press office at the state department. A state department spokesperson would not answer questions about the records, saying that as a general practice, they do not comment on personnel matters.

Harding left the embassy in July 2020, though he remains in Samoa, according to his LinkedIn account.

Kennedy ultimately visited in June 2019. While there, he and his wife, the actress Cheryl Hines, were photographed greeting the prime minister during an Independence Day celebration. He also met with government health officials as well as a group of figures who have cast doubt on vaccines, including Tamasese.

The Guardian and the AP could find no record of Kennedy publicly discussing the purpose of his trip until after measles struck. In 2021, he wrote that he went there to discuss “the introduction of a medical informatics system” to track drug safety. He said Samoan officials “were curious to measure health outcomes following the ‘natural experiment’ created by the national respite from vaccines”.

Since then, he has said his reason for going to Samoa was not related to vaccines.

Redwood, the former Children’s Health Defense president who made early outreach to Samoa, is now an employee at HHS, reportedly working on vaccine safety.

During the measles outbreak, Kennedy wrote a four-page letter to Samoa’s prime minister suggesting without evidence that the measles infections were due to a defective vaccine and floating other unfounded theories.