Shingles Vaccine Dementia Risk, Maltbook AI, Pacific Microplastics, and Lunar Race Updates | Naked Scientists

Four science topics anchor this Naked Scientists episode: a Lancet Neurology study suggests shingles vaccination may reduce dementia risk, with Welsh, Canadian, and Australian data supporting the finding. The show also explores Maltbook, a social network for AI tools, and the questions it raises about AI-generated content. A Pacific Islands microplastics study highlights contamination in fish and the case for a global plastic treaty. Finally, a NASA hydrogen-leak delay fuels discussion about the US and China lunar race, including launch windows, lunar landers, and the evolving space capabilities of both nations. Host Chris Smith guides the conversations with expert guests and critical questions about the science behind the headlines.

Shingles vaccine and dementia risk

The episode begins with a discussion of a recent study published in The Lancet Neurology that suggests herpes zoster vaccination reduces dementia risk by about 20 percent. The Naked Scientists team traces how a natural experiment in Wales used date-of-birth cutoffs to create clean comparison groups, enabling a clearer view of dementia outcomes after vaccination. Canadian primary care data from Ontario were then examined to see if the same patterns held, with Australian data also contributing to the cross-country validation. Experts discuss two potential mechanisms: one, that reactivation of the chickenpox virus drives age-related inflammation linked to dementia, and two, broader immune system effects from vaccines that influence health beyond the targeted response. The discussion emphasizes that shingles vaccination is inexpensive, widely accessible, and safe, though a large-scale clinical trial with the old live vaccine would be ideal to conclusively establish causality.

"It\'s a one-off, inexpensive, simple, readily available, safe intervention." - Pascal Geletzer, Stanford University

AI agentic systems and Maltbook

The conversation then shifts to artificial intelligence and agentic AI, with Maltbook described as a social network for AI tools to communicate with one another. The BBC’s Zoe Kleinman explains how the site claims that humans can read but cannot post, and how the conversations appear to be AI-generated discussions among tools. The hosts and Kleinman examine whether real AI agents discover information autonomously or whether humans are steering the interactions. They also discuss broader concerns about AI-generated content and the potential for low-quality or misleading information to pollute the knowledge base that future AI systems learn from, a worry shared by many publishers about content quality and trust.

"Maltbook claims to be a sort of social network for AI tools to chat amongst themselves, and what\'s on there has people both intrigued and spooked in equal measure" - Zoe Kleinman, BBC technology correspondent

Microplastics in remote Pacific fish and global treaty context

The programme then turns to plastic pollution, highlighting a study from the University of the South Pacific showing microplastics in about a third of fish from remote Pacific islands. The discussion connects these findings with prior work in the English Channel and emphasizes how the type and density of plastics affect different species across ocean domains. Richard Thompson explains that plastic particles can carry adsorbed chemicals, increasing toxicity risk, and notes that a legally binding global treaty is crucial to curb plastic pollution. The host underscores the persistence of legacy plastics and the need for safer chemical formulations in plastics as the world negotiates international action.

"it\'s not just the plastic that\'s the threat, it\'s the stuff that sticks to the plastic" - Richard Thompson, University of Plymouth

The US lunar delay and the China lunar ambitions

The final segment surveys spaceflight politics and technology, focusing on NASA\u2019s hydrogen leak delaying the Artemis window by at least one month. The discussion analyzes why such delays matter for the race to return humans to the Moon and how China\u2019s progress, including lunar lander tests and operations on the Tiangong space station, may confer an advantage. The hosts compare launch windows, orbital dynamics, and landing site considerations, with comments on China\u2019s unaired publicity approach versus the more public NASA narrative. The space-science guest emphasizes that China may opt for a simpler initial landing strategy near the equator, given the Moon\u2019s challenging surface near the poles. The conversation closes with a sense of cautious optimism about future milestones in lunar exploration.

"Not very satisfactory. There\'s not a great explanation." - David Whitehouse, space scientist and author

The episode ends with a look ahead to future topics and thanks to supporters, inviting listeners to engage with the show and its science-driven content.