The number of confirmed cases of measles near Portland increases to 30 on Friday – an outbreak stimulated by lower than normal levels of vaccination at the so-called "hot spot".
Public health representatives in southwest Washington, just across the Columbia River from Portland, Oregon, say people may have been exposed to the dangerous disease in more than three dozen locations, including Portland International Airport, Portland Trail Blazers, a place in the Amazon Locker and stores such as Costco and Ikea.
Twenty-six of the confirmed patients were not vaccinated against measles and the vaccination status of four other infected subjects was unknown. One child is hospitalized. Authorities say nine more cases are suspected.
Most of the cases include children under the age of 10, says a Clark County Public Health Department statement. An adult is infected, and the rest are teenagers.
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Washington Governor Jay Insule, a Democrat, announced Friday a state emergency health emergency. Authorities in neighboring Oregon and Idaho issued warnings.
Inslee said the number of cases "creates an exceptional risk to public health that can quickly spread to other countries."
The measles vaccine has been part of routine childhood shots for decades, and measles has been declared to be eliminated in the United States in 2000.
But measles is still a big problem in other parts of the world. Passengers infected abroad can bring the virus into the country and spread it, causing recurrent outbreaks.
Last year there were 17 outbreaks and about 350 cases of measles in the United States.
Officials are still not sure where the outbreak of the Pacific Northwest began. The first known patient sought medical attention on December 31, but it is not known whether other people had previously had illness and had not sought treatment. So far, public health officials are targeting more exposure.
It may take weeks or even months before a "delicately contagious" virus has taken place in Washington, said Dr Alan Melnik, Clark County Health Director, on Friday.
People who decide not to vaccinate their children underestimate the dangers of the disease, says Melnik, who himself had measles as a child before the vaccine was common.
Before the vaccine, 400-500 people die of measles each year, 50,000 people are hospitalized, and 4,000 people develop brain edema that can cause deafness, he said. Between one and three cases out of every 1000 are fatal, he said.
"This is one of the most contagious viruses we have, there may be really serious complications … and it is completely preventable with an incredibly cheap and safe vaccine," said Melnik.
Clark County has already spent more than $ 100,000, trying to keep the hearth, and staff are pulled from other duties, including restaurant inspections, he said.
"Everything is on the deck, obviously it will cost hundreds of thousands of dollars, and it would not surprise me if we were in the seven figures until we were here," he said. "These costs could be prevented if we were all vaccinated."
Clark County, which includes Portland's bedroom in Vancouver, Washington, has a 78% vaccine vaccination rate, well below 92% to 94%, required for so-called "herd immunity," said Marissa Armstrong, spokeswoman for the department.
The immunity of the flock occurs when unvaccinated individuals are protected from infection because almost all of them are vaccinated and immune to disease.
The rate of vaccination against measles for 2-year-olds in County of Malta where Portland lived was 87% in 2017, according to state data. The measles vaccine consists of two shots, one of which is given at age 2 and the second usually between 4 and 6 years.
The data on Portland's vaccination rates for both shots were not immediately available.
Two doses of childhood vaccine are 97% effective and provide immunity for life. One dose is about 93% effective.
Both Washington and Oregon allow vaccine release for personal and philosophical reasons. The amount of vaccinations in Clark County for non-medical reasons is high – 7.5%, Armstrong said.
The incubation period for measles is seven to 21 days, which means that an unvaccinated person who has been exposed can go public for up to three weeks before he or she becomes ill. Patients remain infected four days after they develop a rash.
The virus that spreads through coughing or sneezing can remain in the air for up to two hours in an isolated space. Nine percent of people exposed to measles who have not been vaccinated will receive it.
Every time an unvaccinated person who has been exposed to measles comes out publicly, "he starts this watch again," Armstrong said.
Earlier this week, the authorities were able to identify several people who were exposed but are not yet ill. These people stayed home and later became ill, Armstrong said.
Those who may have been exposed should observe the early symptoms of fever and malaise, and then a rash beginning on the head and moving on the body. In some cases, serious complications such as pneumonia and brain infections can occur.