Experts worry it will be used to further Robert F. Kennedy Jr.'s anti-vaccine agenda. Get your news from a source that's not owned and controlled by oligarchs. The US Department of Health and Human Services (HHS) is developing a generative artificial intelligence tool to find patterns across data reported to a national vaccine monitoring database and to generate hypotheses on the negative effects of vaccines, according to an inventory released last week of all use cases the agency had for AI in 2025. The tool has not yet been deployed, according to the HHS document, and an AI inventory report from the previous year shows that it has been in development since late 2023. But experts worry that the predictions it generates could be used by HHS secretary Robert F. Kennedy Jr. to further his anti-vaccine agenda.

Experts worry Robert F. Kennedy Jr.'s Health Department will use an internal AI tool to analyze vaccine injury claims in a way that furthers his anti-vaccine agenda. The US Department of Health and Human Services is developing a generative artificial intelligence tool to find patterns across data reported to a national vaccine monitoring database and to generate hypotheses on the negative effects of vaccines, according to an inventory released last week of all use cases the agency had for AI in 2025. The tool has not yet been deployed, according to the HHS document, and an AI inventory report from the previous year shows that it has been in development since late 2023. But experts worry that the predictions it generates could be used by Health and Human Services secretary Robert F. Kennedy Jr. to further his anti-vaccine agenda. A long-standing vaccine critic, Kenedy has upended the childhood vaccination schedule in his year in office, removing several shots from a list of recommended immunizations for all children, including those for Covid-19, influenza, hepatitis A and B, meningococcal disease, rotavirus, and respiratory syncytial virus, or RSV.

Epidemic outcomes have a complex interplay with human behavior and beliefs. Most of the forecasting literature has focused on the task of predicting epidemic signals using simple mechanistic models or black-box models, such as deep transformers, that ingest all available signals without offering interpretability. However, to better understand the mechanisms and predict the impact of interventions, we need the ability to forecast signals associated with beliefs and behaviors in an interpretable manner. In this work, we propose a graph-based forecasting framework that first constructs a graph of interrelated signals based on trend similarity, and then applies graph neural networks (GNNs) for prediction. This approach enables interpretable analysis by revealing which signals are more predictable and which relationships contribute most to forecasting accuracy. We believe our method provides early steps towards a framework for interpretable modeling in domains with multiple potentially interdependent signals, with implications for building future simulation models that integrate behavior, beliefs, and observations.

In this work, we study English-language vaccine discourse in social media posts, specifically posts on X (formerly Twitter), in seven years before the COVID-19 outbreak (2013 to 2019) and three years after the outbreak was first reported (2020 to 2022). Drawing on theories from social cognition and the stereotype content model in Social Psychology, we analyze how English speakers talk about vaccines on social media to understand the evolving narrative around vaccines in social media posts. To do that, we first introduce a novel dataset comprising 18.7 million curated posts on vaccine discourse from 2013 to 2022. This extensive collection-filtered down from an initial 129 million posts through rigorous preprocessing-captures both pre-COVID and COVID-19 periods, offering valuable insights into the evolution of English-speaking X users' perceptions related to vaccines. Our analysis shows that the COVID-19 pandemic led to complex shifts in X users' sentiment and discourse around vaccines. We observe that negative emotion word usage decreased during the pandemic, with notable rises in usage of surprise, and trust related emotion words. Furthermore, vaccine-related language tended to use more warmth-focused words associated with trustworthiness, along with positive, competence-focused words during the early days of the pandemic, with a marked rise in negative word usage towards the end of the pandemic, possibly reflecting a growing vaccine hesitancy and skepticism.

The vaccine advisory group ACIP, not all members of which seemed to know what the group does, recommended to the CDC that combined MMRV shots not be given before age 4. A federal vaccine advisory committee made of members hand-picked by Health and Human Services Secretary Robert F. Kennedy Jr. recommended in an 8-3 vote on Thursday that the combined measles, mumps, rubella and varicella (MMRV) vaccine should not be given before age four, citing long-known evidence that shows a slightly increased risk for febrile seizures in that age group. Experts say that while frightening, febrile seizures--which are uncommon after vaccination--are usually short-lived and harmless, and removing the option for parents could cause a decline in immunization rates against measles, mumps, and rubella, some of the most dangerous childhood diseases. Known as the Advisory Committee on Immunization Practices, or ACIP, the group provides recommendations to the US Centers for Disease Control and Prevention on vaccine usage. These recommendations are typically adopted by CDC and have an impact on state vaccine requirements for school, insurance coverage of vaccines, and pharmacy access--something at least one member of the panel seemed to be unaware of. Thursday's vote is part of a new shift in vaccine policy being spearheaded by Kennedy, a longtime anti-vaccine activist.

Fired CDC Director Says RFK Jr. Pressured Her to Blindly Approve Vaccine Changes Susan Monarez told a Senate committee that Robert F. Kennedy Jr. demanded she dismiss career officials without cause--and accept vaccine recommendations regardless of whether science backed them up. Susan Monarez testifies before the Senate on June 25, 2025. At a Senate hearing on Wednesday, former director of the US Centers for Disease Control and Prevention Susan Monarez said she was fired from her role for not rubber-stamping vaccine recommendations from her boss, Health and Human Services secretary Robert F. Kennedy Jr., regardless of whether they were backed by scientific evidence. Just two months after Monarez was sworn in to the job, HHS announced on August 27 that she was no longer the director of the CDC. She had been the acting director since January and was the first CDC director to receive Senate confirmation after a law took effect this year requiring the president's nominee to receive Senate approval.

Speaking at a WIRED event Tuesday, Moderna CEO Stéphane Bancel said he was "encouraged" by the company's dialogue with the FDA--but acknowledged recent setbacks. Moderna CEO Stéphane Bancel prepares to testify before the Senate on March 22, 2023 in Washington, DC. At the WIRED Health summit on Tuesday, Moderna CEO Stéphane Bancel said the recent changes to Covid-19 vaccine policy made by Health and Human Services secretary Robert F. Kennedy, Jr. are a "step backward." Moderna is one of the manufacturers of mRNA-based Covid-19 vaccines, and last month the company received approval from the Food and Drug Administration for an updated version of the shot . But as part of that approval, the FDA imposed new restrictions on who can receive the vaccine.

Large Language Models (LLMs) are a double-edged sword capable of generating harmful misinformation -- inadvertently, or when prompted by "jailbreak" attacks that attempt to produce malicious outputs. LLMs could, with additional research, be used to detect and prevent the spread of misinformation. In this paper, we investigate the efficacy and characteristics of LLM-produced jailbreak attacks that cause other models to produce harmful medical misinformation. We also study how misinformation generated by jailbroken LLMs compares to typical misinformation found on social media, and how effectively it can be detected using standard machine learning approaches. Specifically, we closely examine 109 distinct attacks against three target LLMs and compare the attack prompts to in-the-wild health-related LLM queries. We also examine the resulting jailbreak responses, comparing the generated misinformation to health-related misinformation on Reddit. Our findings add more evidence that LLMs can be effectively used to detect misinformation from both other LLMs and from people, and support a body of work suggesting that with careful design, LLMs can contribute to a healthier overall information ecosystem.

Background Advances in machine learning (ML) models have increased the capability of researchers to detect vaccine hesitancy in social media using Natural Language Processing (NLP). A considerable volume of research has identified the persistence of COVID-19 vaccine hesitancy in discourse shared on various social media platforms. Methods Our objective in this study was to conduct a systematic review of research employing sentiment analysis or stance detection to study discourse towards COVID-19 vaccines and vaccination spread on Twitter (officially known as X since 2023). Following registration in the PROSPERO international registry of systematic reviews, we searched papers published from 1 January 2020 to 31 December 2023 that used supervised machine learning to assess COVID-19 vaccine hesitancy through stance detection or sentiment analysis on Twitter. We categorized the studies according to a taxonomy of five dimensions: tweet sample selection approach, self-reported study type, classification typology, annotation codebook definitions, and interpretation of results. We analyzed if studies using stance detection report different hesitancy trends than those using sentiment analysis by examining how COVID-19 vaccine hesitancy is measured, and whether efforts were made to avoid measurement bias. Results Our review found that measurement bias is widely prevalent in studies employing supervised machine learning to analyze sentiment and stance toward COVID-19 vaccines and vaccination. The reporting errors are sufficiently serious that they hinder the generalisability and interpretation of these studies to understanding whether individual opinions communicate reluctance to vaccinate against SARS-CoV-2. Conclusion Improving the reporting of NLP methods is crucial to addressing knowledge gaps in vaccine hesitancy discourse.

Can we simulate a sandbox society with generative agents to model human behavior, thereby reducing the over-reliance on real human trials for assessing public policies? In this work, we investigate the feasibility of simulating health-related decision-making, using vaccine hesitancy, defined as the delay in acceptance or refusal of vaccines despite the availability of vaccination services (MacDonald, 2015), as a case study. To this end, we introduce the VacSim framework with 100 generative agents powered by Large Language Models (LLMs). VacSim simulates vaccine policy outcomes with the following steps: 1) instantiate a population of agents with demographics based on census data; 2) connect the agents via a social network and model vaccine attitudes as a function of social dynamics and disease-related information; 3) design and evaluate various public health interventions aimed at mitigating vaccine hesitancy. To align with real-world results, we also introduce simulation warmup and attitude modulation to adjust agents' attitudes. We propose a series of evaluations to assess the reliability of various LLM simulations. Experiments indicate that models like Llama and Qwen can simulate aspects of human behavior but also highlight real-world alignment challenges, such as inconsistent responses with demographic profiles. This early exploration of LLM-driven simulations is not meant to serve as definitive policy guidance; instead, it serves as a call for action to examine social simulation for policy development.