Samoa's prime minister and director-general of health have lambasted Robert F. Kennedy Jnr's vaccine misinformation.

Kennedy, the nephew of former president John F. Kennedy, son of former Attorney General Robert Kennedy, and new US President Donald Trump's pick to lead the country's health agency, faced angry Democrat lawmakers in a senate hearing this week over his controversial views surrounding vaccines.

During a visit to Samoa in 2019, Kennedy, who denies being anti-vaccine, met with government representatives and anti-vaccine influencers four months before a measles outbreak which killed 83 people was declared.

He was accused of stoking anti-vaccine sentiment and running a disinformation campaign.

On Friday, Samoa's Prime Minister, Fiame Naomi Mataʻafa, told The Guardian that if Kennedy was the "messenger for anti-vaxxers, as a leader, I do not agree with him".

During his confirmation hearing, when pressed by Democrats, Kennedy said tissue samples tested in New Zealand didn't show any trace of measles.

"Eighty-three people died. When tissue samples were sent to New Zealand, most of those people did not have measles, we do not know what was killing them," he said.

The outbreak saw a significant drop in vaccination rates, fuelled by anti-vaccination sentiment and stemming from a vaccination error the previous year where two nurses incorrectly administered a vaccine mixed with expired muscle relaxant.

By 2019, abetted in part by the failure of the Samoan government's public health messaging and people blaming the infants' deaths on the MMR vaccine, the WHO said vaccination rates had fallen to 31 per cent, down from 84 per cent in 2015.

"The facts remain that the two babies who died were through human error of the nurses," Fiame told The Guardian.

"All the different actors, especially anti-vax people, got on board and suggested that the vaccination was the cause, which is complete rubbish."

The resulting outbreak saw at least 83 deaths and over 5700 cases, mostly in young children and infants.

Samoa's director-general of health, Dr Alec Ekeroma, said Kennedy was a "disaster for public health in the world," and called his comments around the outbreak a "complete lie".

"There was only one post-mortem - no tissues were sent to New Zealand for the rest of the deaths in Samoa, because it was not necessary, because it was obvious these people died from measles," Dr Ekeroma told RNZ.

"It was obvious these people died from measles, they are clinical measles, and it looked like measles that killed them."

Kennedy claimed his visit to Samoa had nothing to do with vaccines, but multiple people have said he met with anti-vaccine campaigners, despite not making any public speeches on the topic.

"To have an anti-vaxxer at the top of the United States health system is not good for anyone," Dr Ekeroma said.

He said the vaccination rates had once again risen to over 80 per cent on the island.