FILE - A medical doctor holds a vial of the combination measles, mumps and rubella vaccine at Prisma Health Pediatrics in Greer, S.C., on March 18, 2026.
Mary Conlon / AP
Health officials in Oregon are concerned they may not be able to contain a small but growing measles outbreak, and on Friday they asked for the public’s help in turning the tide.
In one sign of the mounting outbreak, Oregon recently saw its first hospitalization due to the measles, state epidemiologist Dr. Dean Sidelinger reported. The hospitalized person has been discharged and is recovering, Sidelinger said in a press conference Friday.
Saying the situation is growing more urgent, he urged parents who are on the fence about the measles vaccine to talk to their child’s health care provider about it.
Oregon has counted 20 known cases of measles so far this year, although state officials have repeatedly said they believe there are far more cases in Oregon going unreported. Sidelinger said there are mounting signs that transmission of the virus is becoming more widespread in Multnomah and Clackamas counties.
Just this week, the Oregon Health Authority announced that a middle school, a community college and an urgent care were all sites of potential measles exposures.
Related: Measles cases in Oregon are ticking up. Here’s what you need to know
On April 11, public health officials identified Oregon’s first outbreak this year that involved more than a single household, involving measles cases in Multnomah and Clackamas counties. The Centers for Disease Control and Prevention defines an outbreak as three or more linked cases.
The risk to the majority of the public is low because a large majority of Oregonians have been vaccinated against measles. A single dose of the shot provides strong prevention against infection, and that protection lasts throughout a person’s lifetime with little waning of immunity.
Sidelinger said he believes a major driver of transmission in Oregon is people who have the virus, aren’t stick enough to seek medical care, and go on to spread it to other unvaccinated people.
When people with measles are seen by a doctor or get a lab test, medical providers are required to report those cases directly to public health officials, so they can help identify anyone else who might have been exposed. If the virus is spread by people who do not seek medical care, there is little opportunity for public health to intervene.
Protecting the unvaccinated
Measles is among the most contagious respiratory diseases in the world.
Unvaccinated pregnant people, unvaccinated people with a weakened immune system, and infants under 12 months old are at higher risk of catching measles if they are exposed, and also of getting a more serious infection.
Families that have conclusively decided not to vaccinate can help limit the spread of measles by quarantining themselves if they get sick, and by wearing a mask and calling ahead if they go to urgent care or a hospital.
“We do rely on cooperation from others and, and people to take some simple steps to protect their family and loved ones,” Sidelinger said.
There is no specific antiviral treatment that can cure measles, though doctors can provide supportive care to keep patients hydrated and address symptoms like a fever.
Related: Measles has reached a Portland school. Here’s why health officials think they can stop it
It can be serious in children under five years old. As many as one in every 20 children who gets measles develops pneumonia. In rarer cases, it can cause life-threatening swelling in the brain.
“Prevention is absolutely critical,” said Dr. Dawn Nolt, a professor of pediatrics at OHSU.
The United States has decades of experience with measles and a highly effective vaccine that doesn’t require regular boosters.
“If we can get one shot in everyone, we stop this in its tracks,” Nolt said.
Sidelinger said he is particularly concerned that an unvaccinated person or people have brought measles into two schools this week.
Because measles spreads quickly to people who have not been vaccinated, those exposures rapidly expanded the pool of unvaccinated students who could contract the disease and then go on to unwittingly spread it to other classmates and staff. Per state policy, any unvaccinated student or staff person who is exposed to measles is excluded from school for several weeks — and that can add up for children exposed more than once.
“It risks bringing to a halt the whole reason these students are at schools learning, academic achievement, social connection,” Sidelinger said.
Related: Measles cases in Oregon are ticking up. Here’s what you need to know
In South Carolina, the state with the largest outbreak so far in the United States, the vast majority of measles cases have been reported in children. Schools have been one major hub of transmission and some unvaccinated students have had to quarantine themselves repeatedly during that extended outbreak.
In Oregon, about 6% of kindergarteners have a non-medical exemption allowing them to opt out of the first dose of the two-dose measles vaccine, which is otherwise required for school attendance. That amounts to more than 10,000 children in the state without protection against the virus.
Measles was declared eradicated in the United States in 2000. But waning vaccination rates have allowed the virus to gain a foothold again. In 2025, the United States reported more than 2,000 cases of measles, and diagnoses are on track to far exceed that number this year.
