An outbreak of measles that continues to spread near the Portland area has health officials on high alert in Jackson County, where low immunization rates in some areas could spell chaos with just one infection.
No Ashland K-12 school, for example, has more than 84 percent of students who are fully vaccinated against measles.
“It’s really a matter of when, not if, we’re going to have a measles outbreak,” said Jackson County health officer Dr. Jim Shames, “unless something changes those dynamics.”
Shames said that herd immunity against measles is achieved when between 92 and 94 percent of the population is vaccinated.
“The level of concern is pretty high,” he said of the Clark County, Washington, outbreak. “It’s episodically high, and we’re going to do our best to pass info on to the public that they need, and to prepare as best we can for the possibility of an outbreak of measles here in Jackson County.”
The number of confirmed measles cases near Portland rose to 37 Tuesday. The majority of cases are in children, and 32 of them involve unvaccinated people, according to the website for Clark County, Washington, Public Health Department.
Only one case has been confirmed in Oregon. Clark County and Multnomah County health departments have published lists of the dates, times and places people might have been exposed to the virus.
Even 287 miles south, that list can hit close to home — like when a group of students from Logos Public Charter School in Medford visited the Oregon Museum of Science and Industry a few days after a possible exposure window identified by Multnomah County.
It was too long after the measles virus could have lingered in the environment, but Logos Executive Director Sheryl Zimmerer posted information from the Oregon Department of Education on the school’s Facebook page about the visit and how the school would handle possible infections.
“Parents are not concerned at this point,” she said in a text message Tuesday.
Among K-12 students in Jackson County, 93 percent reported having received both required doses of the measles vaccine, according to Oregon Health Authority data.
Children receive only the first round of the MMR (measles, mumps and rubella) vaccine before entering kindergarten, which is why OHA’s data for preschools and child care facilities tracks only the first dose.
The rate dips slightly countywide in that age group: 87 percent of pre-K children had received the first dose, which Shames said provides individuals about 93 percent effective immunity.
The lowest percentage, according to the OHA, is Siskiyou School, where only 29 percent of students received the second dose of MMR.
As with many infectious diseases, young, elderly and immuno-compromised people are the most vulnerable to the disease. Measles is highly contagious, lingering in the air for a couple of hours after an infected person has coughed or sneezed.
If a person is infected, 90 percent of the people around him or her will also become infected if they are not protected, according to the Centers for Disease Control and Prevention.
Tanya Phillips, Jackson County’s health promotion manager, said her department is working with renewed vigor to educate the public in light of the Clark County outbreak.
Through coordination with health care providers and schools, she said, the department is trying to spread information about not only immunization, but also response if infection should occur.
“It is the medical community as a whole, like a primary care provider who is offering vaccines to their patients, that can have those conversations, as well,” she said, “so we definitely provide that information through different avenues.”
Shames said people can build up antibodies within the first few days of receiving the vaccine. Sometimes people respond to news of outbreaks by going to get vaccinated, or having their children vaccinated to keep them in school, he said.
“If you were exposed to measles and you got a measles shot immediately, you could dodge the bullet,” he said. “It could be that by the time the virus is starting to replicate in your body, you might have enough antibodies to either inhibit the disease entirely or make it a milder case.”
What you need to know to respond
Response to a measles infection can play an important role in determining whether the disease spreads.
If you suspect that you or someone you are responsible for has contracted measles, first call your primary care provider — venturing out in public or to a doctor’s office can greatly increase the risk of spreading the infection if you have it, said Dr. Jim Shames, Jackson County’s health officer.
Early symptoms of measles include a fever, cough, runny nose and red eyes. Diarrhea and ear infections are also associated with the disease. The red blotchy rash characteristic of the disease typically starts near the ears or forehead before spreading to the face and the rest of the body.
If you have been exposed to measles, getting immunized within three days can help mitigate symptoms or stave off the disease, Shames said. Treatment after infection is aimed only at reducing symptoms, as measles is caused by a virus.
Reach Mail Tribune reporter Kaylee Tornay at email@example.com or 541-776-4497. Follow her on Twitter @ka_tornay.