Newly released letters undercut Health Secretary Robert F. Kennedy Jr.'s sworn-hearing claim that his 2019 Samoa trip had nothing to do with vaccines, a problem for him as measles outbreaks spread across the U.S.

• A short letter Kennedy sent to Samoa's prime minister mentions vaccines repeatedly and proposes his team investigate the country's MMR shots.
• At his confirmation hearing he told senators repeatedly the trip had nothing to do with vaccines; the health department calls any accusation of lying defamatory.
• Samoa suffered a huge measles outbreak shortly after the visit that killed 83 people, most of them small children.
• New U.S. cases are piling up — deaths in Pennsylvania, five confirmed cases in Ohio's Wayne County, and four tied to an Atlanta daycare, all among unvaccinated people.
• Kennedy is fighting back publicly, accusing Pennsylvania's governor of political fear-mongering and suggesting the reported deaths were premature or made up.

Outlook: Expect more outbreaks and growing pressure on Kennedy to produce evidence for his vaccine claims or face questions about whether he misled Congress.