By Clea Skopeliti Published on 16/04/2025 - 16:43 GMT+2 Most of the top-performing posts analysed were found to contain misinformation, according to social media researchers. ADVERTISEMENTSocial media posts about US Health Secretary Robert F Kennedy Jr and vaccines have received major engagement among European social media users this year, Euronews can reveal, leading to concerns about the spread of misinformation as measles cases rise in Europe. Posts related to both RFK Jr and vaccines shared by accounts in French, German and Italian on X received nearly a million likes, shares and comments in the first quarter of 2025. More than half of the top-performing posts analysed were found to be spreading misinformation, researchers found. US President Donald Trump’s health secretary has repeatedly cast doubt on the safety of vaccines.The social media analysis, carried out by misinformation researchers at Ripple Research, logged some 220,000 posts mentioning RFK Jr and vaccine-related keyword searches in three languages between January and March.  The captured posts regarding RFK Jr and vaccines were authored by 53,000 users and engaged with 948,000 times, Ripple Research’s analysis found. It comes against the backdrop of mounting concerns about falling immunisation rates against measles, as the number of measles cases in the European region doubled last year and reached the highest rate in 25 years, according to the World Health Organization and the UN children's fund, UNICEF.UNICEF is conducting a study in Romania and France to understand immunisation, Euronews was told, and preliminary data shows one in two caregivers there reported that social media influenced their decision on whether or not to be vaccinated.'Clear connection' between misinformation and outbreaks"There were more than 100,000 measles cases in Europe alone in 2024. A third of global cases were in Europe," Alexei Ceban, immunisation specialist at Unicef Europe and Central Asia Regional Office, told Euronews."There are significant gaps in immunisation coverage: five in the top 10 countries in Europe and Central Asia were in Europe," Ceban added, commenting on current measles outbreaks."Most of the time, we’ve thought that measles, or other vaccine-preventable diseases, may be registered in other, lower-income countries, but that is not the case." "I think that misinformation affects immunisation coverage and we see a clear connection between these two phenomena … which leads to huge outbreaks," he pointed out. Ceban called for "timely immunisation". "Children are dying, or suffering serious consequences… pneumonia, blindness. Measles is a severe disease."In the US, more than 700 measles cases have been reported in outbreaks across the country. Two children have been confirmed to have died from measles in 2025. RFK Jr, who has previously made unsupported claims regarding the safety and efficacy of the measles-mumps-rubella (MMR) vaccine, last week made his strongest comment in favour of the vaccine so far, telling the public that it "is the most effective way to prevent the spread of measles."  RFK Jr has also triggered a backlash after he claimed that increasing autism rates were the result of “an environmental toxin,” as he announced that his department would undertake a massive effort to determine the cause of the developmental disorder. ADVERTISEMENTTrump has also suggested that vaccines could be to blame for autism rates, despite decades of research concluding there is no link between the two. Scientists have found no evidence of increased rates of autism among those who are vaccinated compared to those who are not.Anti-vaccine narratives surgeMeanwhile, social media networks have not found an efficient way to rein in misinformation and conspiracy theories, and some decisions have opened the possibility of their further spread.After Elon Musk bought Twitter and rebranded it as X in October 2022, which led to the firing of its fact-checkers, experts have warned that misleading information has spread more easily since. In January, Meta announced it was abandoning its use of independent fact-checkers on its Facebook and Instagram platforms, with the plan to replace them instead with X-style "community notes".ADVERTISEMENT"We immediately saw an outpouring of misinformation that was being reined in a little before. It just opened the floodgates," Prof Heidi Larson, the head of the Vaccine Confidence Programme at the London School of Hygiene and Tropical Medicine, told Euronews. "We need to get real about the situation — we can’t rely on their fact-checking, and we need to think of ways to get more honest information out there." Larson reflected on how anti-vaccine or vaccine-hesitant views had moved from a fringe position into the mainstream over the past two decades. RFK Jr's position as US health secretary "empowers them on whole different level, it’s harder to be dismissive when someone in his position is saying the same," Larson told Euronews. However, the US health secretary rejects the "anti-vaccine" label, she pointed out. "He claims to be ‘pro safety’, not against vaccines." Yet, this can still empower those prone to conspiracy theories, Larson explained.ADVERTISEMENTLarson warned that there was an "additional risk" that people who had previously felt confident in taking vaccines might be influenced against them. "That they see so much of this other view that starting to question when they weren’t before, and then start to spread it and say, ‘I heard this, what do you think?’"COVID jabs also targetedThe researchers identified three key moments in which posts about the US health secretary surged on X and the misinformation narratives that accompanied them.Posts in French, Italian, and German discussing vaccines and RFK Jr spiked at the end of January after senators questioned him at his confirmation hearing. Six of the 10 top-performing posts analysed at this time were found to contain misinformation, the researchers said, including posts amplifying RFK Jr's claims regarding the risks of COVID-19 vaccines. ADVERTISEMENTThe scientific consensus is that the risks from the COVID-19 vaccines are vastly smaller than those of the disease. As with any medical product, the vaccines are not 100% safe, but most side effects are mild and temporary.Engagement — and the proliferation of anti-vaccine misinformation — surged further the following month during Kennedy's swearing-in ceremony. All of the most successful posts analysed at this time were found to advance misinformation, including Kennedy’s misleading claim about a lack of data on COVID-19 vaccine safety. The safety of the COVID-19 jabs is well established.Users posting on X in the above three European languages once again made misleading and misinformed claims regarding vaccination in late March, following the resignation of the head of the FDA vaccine division, Dr Peter Marks. ADVERTISEMENTThe analysis found that five in 10 of the top-performing posts related to RFK Jr and vaccines at this point contained misinformation, as narratives spread about Marks allegedly "blocking" investigations into vaccine injuries. Marks has told AP that he refused to allow unrestricted access to a tightly held vaccine safety database, fearing that the information might be manipulated. He said that he agreed to grant RFK Jr's team the ability to read thousands of reports of potential vaccine-related issues sent to the government’s Vaccine Adverse Event Reporting System, but he would not allow them to edit the data directly.On X, some called for a similar "purge" of the health system to be enacted in France. ADVERTISEMENTAs they continue to gain prominence, Larson called for "a whole different approach" to tackle the rise of individuals and groups that seek to undermine confidence in vaccines. "We need to find ways beyond fact-checking. These are movements, a whole different approach is needed."COVID blew the roof off the multi-language spread of (these narratives). Nothing stays local, we see people purposefully pushing what we call misinformation … They look for opportunities, and amplify anything that supports that view."Euronews contacted the US Department of Health and Human Services and X for comment.ADVERTISEMENTGo to accessibility shortcuts You might also like