Oregon measles outbreak spreads to 25 cases in three counties

Oregon Health Officials announced Thursday that a measles outbreak in the Willamette Valley has spread to 25 residents, all of whom have not been vaccinated.

The latest outbreak is unusual because the disease is highly contagious and easily controlled through vaccination, but health officials say vaccination rates have fallen in recent years, leading to recurring outbreaks.

The most recent outbreak occurred two months ago, and the state Unvaccinated adult contracts virus in Marion CountyThe adult then transmitted the measles to an unvaccinated child in the same household.

To date, there have been 16 cases in Marion County, eight in Clackamas County and one in Multnomah County, according to Dr. Paul Cieslak, medical director for the Oregon Health Authority. Five of the cases are in adults over the age of 20 and the rest are in people under the age of 20.

Cieslak said the current outbreak is the state's largest since 2019, when the state saw 28 cases. (Clark County, just across the Columbia River, had a “much larger outbreak” that year, he added.)

Health officials say measles is a highly contagious airborne virus that can remain contagious for up to two hours after an infected person has left the area. Measles remains contagious before the rash appears and for up to four days after the rash appears, meaning people may not yet know they have measles and could unknowingly spread it to others.

Symptoms include fever, cough, runny nose, and red eyes, usually followed by a rash that starts on the face and spreads to other parts of the body. These symptoms begin 7 to 21 days after exposure to the infection.

Officials said the potentially deadly measles outbreak poses the greatest risk to people who have not been vaccinated against measles, pregnant women, babies under one year old and those with weakened immune systems.

Before the measles vaccine was available, an average of 400 to 500 people died from the measles virus each year in the United States. According to the Centers for Disease Control and PreventionIn 2000, after three decades of vaccination efforts, the United States eradicated the virus.

Cieslak said Oregon's last measles outbreak before 2019 was in the 1990s, and he attributed that to the state's “very high vaccination rates and very high levels of population immunity.”

“Unfortunately, we're seeing a decline in the percentage of people getting vaccinated against measles,” he said.

Last school year, Oregon had the second-highest rate of non-medical exemptions in the country. Centers for Disease Control and PreventionOfficials say the measles-rubella-mumps vaccine is highly effective against measles, but only if enough people are vaccinated.

Before 2000, about 1 percent of the state's kindergartners had non-medical exemptions from school-mandated vaccinations, Cieslak said. But that number has been steadily increasing, he said. Last school year, about 9 percent of the state's kindergartners had non-medical exemptions.

“This threatens herd immunity,” Cieslak said, referring to widespread immunity to the disease among large populations. “Measles is probably the most contagious disease we know of. You need very high levels of herd immunity to stop the transmission of this infectious disease.”

Clackamas County Health Officer Dr. Sarah Present said having a large number of people who haven't been vaccinated against measles could put the community at risk.

“Measles is a serious disease. It's not just a mild rash. There are so many complications,” she said. “The burden of not being able to go to school if you have this disease is huge. Of course, the burden of getting the disease is even greater.”

Officials are urging anyone experiencing measles symptoms to call a health care provider or urgent care center ahead of time and to make a plan to avoid spreading the disease to others in the facility.

— Christine de Leon We cover news for the retail industry, small business and data enterprise. Contact us at email address.

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