In this edition: Chronic Lyme, premature babies and jet lag.

Chronic Lyme gets more attention. Long contentious, chronic Lyme, in which symptoms such as fatigue linger long after an infection, has gained more acknowledgment by doctors and investment by researchers. Newer clinical trials are starting to track Lyme patients and investigate potential treatments.

Hospitals and premature babies. Under a new bill, hospitals would be required to disclose how they are equipped to treat extremely premature newborns. The legislation was in part prompted by a Wall Street Journal investigation that found mothers had been told no life-saving measures were possible for extremely premature infants, even though other hospitals nearby would try to save such babies.

RFK Jr. takes steps to remove thimerosal from flu shots. The HHS secretary signed a recommendation from a reshuffled CDC advisory panel that the mercury-based preservative be removed from all flu vaccines. Flu shots that have more than one dose of vaccine contain thimerosal; other versions don’t have it. Some vaccine skeptics say the preservative is linked to autism.

Can apps and hacks prevent jet lag? There are a number of apps that aim to tackle jet lag. Our columnist Sumathi Reddy tried one that had her start adjusting her circadium clock a few days before an overseas trip. Here's how it went, from New York to Greece and back.

How chatbots can fuel delusions. OpenAI’s ChatGPT self-reported it had blurred the line between fantasy and reality with a man on the autism spectrum who later had manic episodes. The chatbot told him he had achieved the ability to bend time. OpenAI said such interactions are rare and therefore unfamiliar to the model, but training is a priority.

“Immersive” digital spa experiences are a thing. At spas and resorts around the world, treatments featuring light shows, sound waves, virtual reality displays and other digital effects are designed to soothe customers struggling with short attention spans.

UnitedHealth confirms Justice Department probes. The company said it was responding to requests from civil and criminal investigators following media reports of probes into its Medicare business. The disclosure follows a series of Wall Street Journal articles in recent months detailing Justice Department investigations of the company.

This newsletter was compiled by the WSJ’s Health & Science team. Follow us on X @WSJHealth and @WSJScience. Email us by replying to this newsletter.