The next two weeks will determine whether a single measles case in Colorado fizzles out or starts an outbreak. An unvaccinated adult who lives in Pueblo developed measles after visiting a part of Mexico that has an ongoing outbreak, according to the Colorado Department of Public Health and Environme nt. The person could have exposed others to the highly contagious disease at Southwest Deli and Cafe in south Pueblo between March 17 and 21 and at Southern Colorado Clinic in west Pueblo from 3:30 to 6 p.m. March 22. Health officials didn’t publicly identify or release any more information about the person, who is recovering from their illness. About 90% of people who don’t have immunity will develop measles if they spend time around a person who is contagious, state epidemiologist Dr. Rachel Herlihy said during a news conference Tuesday. Whether the Pueblo resident’s case remains a one-off or the virus gains a foothold depends on the immunity status of the people around them. About 95% of school-aged children in Pueblo are up-to-date on their measles vaccines, said Randy Evetts, director of the Pueblo Department of Public Health and Environment. The rate is lower among kindergarteners, with about 84% in the city and 92% in the surrounding county fully protected, he said. Typically, someone with measles will develop symptoms such as a fever, cough, runny nose and watery eyes about 10 days after exposure. The rash typically starts about two weeks after exposure, though in some cases the virus can take up to three weeks to cause symptoms, Herlihy said. Patients are contagious about four days before and four days after the rash develops, she said. If someone who visited the deli or the clinic develops symptoms, they should call ahead before seeking medical care so the provider can take precautions to avoid further spreading measles, Herlihy said. “People may have measles and think they have something like a cold,” she said. At the start of March, Herlihy advised people who were behind on their vaccinations to catch up before spring break travel. One dose of the measles vaccine reduces the risk of getting sick by 93%, and two reduce it by 97%. Most people won’t need a booster shot, though adults vaccinated before 1968 should consider one, because the version used in the 1960s was less effective, she said. Typically, children receive their measles shots at about 1 year old and before they start kindergarten. Parents who are concerned about measles can discuss early vaccination with their child’s pediatrician, but most infants would only need an early shot if the family plans to travel to an area with an outbreak, Herlihy said. As of Friday, the Centers for Disease Control and Prevention reported 483 cases of measles in 19 states. Since then, Texas reported 22 additional cases in its outbreak, which accounts for more than 80% of U.S. infections this year. A school-aged child in Texas died of measles in February. An adult in New Mexico who had the virus also died, though health officials are still sorting out whether measles caused that person’s death. The World Health Organization linked some cases in Mexico to the Texas outbreak, but health officials have to wait for genetic sequencing from the Colorado patient’s sample before they’ll know whether that person’s case had roots in Texas, Herlihy said. Related Articles First Colorado measles case since 2023 confirmed in Pueblo Get caught up on measles shots before spring break, Colorado state epidemiologist says On average, about 20% of infected people need hospital care due to pneumonia or other complications. About one in 1,000 children who get measles develop brain swelling, which can cause permanent hearing loss or intellectual disability. Children younger than 5 and adults have a higher risk of complications than older children. The virus can also cause premature birth if an unvaccinated woman gets it during pregnancy. U.S. Secretary of Health and Human Services Robert F. Kennedy Jr. has pushed vitamin A as a treatment for measles. Vitamin A has a role in treating hospitalized children, but parents shouldn’t give it without a doctor’s guidance, Herlihy said. The vitamin builds up in the body, and excessive amounts can cause liver damage, gastrointestinal problems and neurological symptoms in children. Taking too much during pregnancy also can cause birth defects. “We know there is significant toxicity associated with vitamin A,” she said. Sign up for our weekly newsletter to get health news sent straight to your inbox. ...read more read less