Wyoming Warns of Measles Exposure at Grand Teton After 2nd 2026 Case

Q: Beyond the rash, how does measles cause 'immune amnesia,' leaving patients vulnerable for years?

Measles can leave people vulnerable for years because the virus does more than cause fever and rash: it attacks the immune system’s memory. Researchers have found that measles infects immune cells that carry the CD150, or SLAM, receptor, especially memory B cells and T cells, along with some dendritic cells and macrophages. These are the cells that “remember” past infections and help the body respond quickly when those germs return. When measles wipes out many of those memory cells, it can erase a large share of the body’s existing defenses against other diseases. Studies in people and animal models have shown major losses in pre-existing antibodies after measles infection, with some research estimating that 20% to 75% of immune memory can be lost. The immune system then has to rebuild that protection from scratch. That is why the danger from measles often extends well beyond the acute illness. Even after recovery, patients can face two to three years of increased susceptibility to other infections such as pneumonia or diarrheal disease, because their immune system has “forgotten” pathogens it had previously learned to fight. At the same time, the body generates strong new immunity to measles itself, which can mask the broader damage. This is one reason public health officials treat measles as more than a childhood rash. The MMR vaccine prevents not only measles infection and its immediate complications, but also this longer-term immune damage.

1 articles · Updated · WyoFile · Jun 30

June 17-25 exposures may have occurred at Colter Bay Village restaurants, a Colter Bay convenience store and a Target in Jackson after Wyoming confirmed measles in an unvaccinated Teton County adult.
Health officials told potentially exposed people to monitor for symptoms for 21 days and avoid crowded places and high-risk settings, especially if they have not received the MMR vaccine.
The case is Wyoming’s second confirmed measles infection of 2026, after a May case in Fremont County, and follows 14 total cases in 2025 after the state had gone 15 years without one.
Wyoming’s kindergarten MMR coverage was 93.6% in 2025—below the 95% community-immunity threshold—while neighboring Utah has reported 499 measles cases this year.