In June 2019, Robert F. Kennedy Jr. traveled to the small Pacific island nation of Samoa, where he met with activists calling for Samoans to skip measles vaccines and opt for alternatives instead. Now that visit — and the country’s subsequent measles outbreak — are receiving new political attention, as Democrats and advocates seek to block Kennedy’s confirmation as America’s top health official.

Five months after Kennedy’s visit, Samoa declared a measles emergency, with leaders warning that vaccination levels had declined precipitously. Thousands of Samoans were infected during the outbreak, and 83 people died of the vaccine-preventable disease — an episode that Democrats say could foreshadow a future American crisis, should Kennedy be elevated to a Cabinet position and sow doubts about vaccines here. Most of Samoa’s measles deaths were in young children.

“It’s a real-life example of what this individual will [do] as the nation’s leading health care official,” said Hawaii Gov. Josh Green (D), a physician who responded to Samoa’s outbreak five years ago and said he witnessed the deaths of measles-afflicted infants. Green traveled to Capitol Hill this week in a bid to sway senators by sharing his story, part of a larger effort by advocates to scuttle Kennedy’s selection as secretary of health and human services by focusing on the Samoan crisis.

3.14 Action, a liberal-leaning advocacy group, this week began airing an ad featuring Green and others who condemned Kennedy for raising doubts about vaccines ahead of Samoa’s outbreak.

Kennedy, who founded a prominent anti-vaccine group but has maintained that he is not anti-vaccine, has denied any connection with Samoa’s measles outbreak.

“I never told anybody not to vaccinate,” Kennedy told filmmakers for “Shot in the Arm,” a 2023 documentary about vaccine hesitancy that reviewed Samoa’s measles outbreak. He has said he visited Samoa to discuss new ways to oversee the safety of medical interventions after an error preparing vaccines led to two local infants’ deaths.

Spokespeople for the Trump transition team did not respond to requests for comment.

Kennedy is scheduled to visit Capitol Hill this week as he continues meeting with senators ahead of his confirmation hearings.

According to a Washington Post analysis, 20 senators have said they favor Kennedy’s candidacy as HHS secretary, 19 signaled they oppose it, and the positions of the remaining 61 are unclear. Many Democrats have said they will approach Kennedy’s confirmation with an open mind and are refusing to rule out voting for him, though they have cited deep concerns with his views on vaccines.

If Kennedy fails to win support from any Democrats, he can afford to lose only three Republican votes in the closely divided Senate, where he will need 50 votes to be confirmed.

Protect Our Care, a Democrat-aligned advocacy group that opposes Kennedy’s nomination, helped coordinate Green’s visit to Washington — one of several strategies the group has deployed as it targets “up to 10” Republican senators who could vote against Kennedy.

“There’s no silver bullet in a nomination fight,” Protect Our Care executive director Brad Woodhouse said in an interview Monday, adding that his group would continue to highlight other concerns about Kennedy’s record, such as his lack of experience running a major government agency.

“But this [Samoa episode] is a pretty damn big story when you’re talking about turning the reins of health care and public health over to someone like RFK Jr.,” Woodhouse said.

Those concerns have been echoed by American public health experts — and by Samoa’s leaders, who blame Kennedy for fomenting anti-vaccine sentiments in their country ahead of its measles outbreak.

“I hope there is adequate pressure applied to stop Robert F Kennedy’s appointment for the sake of public health in the world,” Alec Ekeroma, director general of Samoa’s Ministry of Health, wrote in an email to The Post.

Vinay Prasad, a University of California at San Francisco professor and epidemiologist, has said Kennedy received too much blame for the measles outbreak.

“I find the narrative that RFK Jr is responsible for the measles deaths in Samoa to be a stretch,” Prasad wrote on Substack last month, adding that he believed the root causes of the outbreak to be systemic and multifactorial.

Samoa’s public health crisis was sparked largely by the deaths of two Samoan infants in 2018 after they received an improperly prepared vaccine targeting measles, mumps and rubella. The country temporarily halted its vaccination program following those deaths, but public confidence in the shots swiftly fell; the World Health Organization estimated that only 31 percent of Samoan infants received measles vaccines in 2018, down from more than 60 to 70 percent in prior years.

Then Kennedy arrived in 2019, and the visit from the high-profile activist harmed efforts to rebuild local trust in vaccines, public health experts have said.

“By meeting with anti-vaccine advocates and amplifying misinformation, Kennedy fueled distrust in a country where vaccination rates had already plummeted due to prior mishandling of vaccines,” Y. Tony Yang, a George Washington University health policy professor who has studied the Samoan outbreak, wrote in an email.

Kennedy’s visit “emboldened the antivaxxers in the country and from overseas who seized on the 2019 measles crisis to sow vaccine hesitancy amongst the population,” Ekeroma wrote in his email.

Advocates are hoping that Green can explain to lawmakers why an overseas public health crisis five years ago is relevant to U.S. political battles today.

The Hawaii governor flew to Washington on a redeye flight Sunday, landing amid Monday’s snowstorm, to meet with senators, share his story of caring for measles-afflicted Samoans and warn about the possible risk to vulnerable populations in the United States.

“My heart broke to see how sick some of these children were,” Green said in an interview. “As a physician in the United States, you almost never see these diseases, because we vaccinate our communities.”

Green said he was hoping to meet with at least five to 10 senators in the coming days and was open to adding meetings — including with President-elect Donald Trump, should his camp be interested. Green declined to disclose the identities of senators planning to speak with him, saying he wanted to keep the focus on Kennedy, the only Trump nominee that the Hawaii governor said he was going to publicly oppose.

“If I didn’t have firsthand experience with the damage that he and his organization caused, I wouldn’t have flown 5,000 miles into a blizzard to meet with these guys,” Green said. “The Republican caucus should insist that President-elect Trump give them a person who has training in public health … who has an understanding of what science does for all of their communities.”

The ads sponsored by 3.14 Action began airing Monday on Fox News, CNN and digital outlets.

Kennedy “is an immediate danger to public health and it’s clear that he cannot be trusted to keep Americans safe and healthy,” Shaughnessy Naughton, president of 3.14 Action, said in a statement. “Senators on both sides of the aisle must hold RFK Jr. accountable for his actions and reject his nomination to Secretary of Health and Human Services.”

Some GOP senators have dismissed questions about Kennedy’s vaccine stance, while others have said they are concerned by his longtime criticism of vaccines. If Kennedy is confirmed, he would be in position to influence America’s vaccination process in a number of ways.

Sen. Bill Cassidy (R-La.), a physician who is the incoming chairman of the Senate’s Health, Education, Labor and Pensions Committee, told “Fox News Sunday” this week that Kennedy was “wrong” on vaccines, but he agrees with him on other issues.

Efforts to question measles vaccines in Samoa ultimately backfired, Ekeroma wrote in his email; the country has since made vaccinations mandatory and instituted a requirement to have vaccination cards at school enrollments.