Public health officials scrambling to contain a measles outbreak in the US Northwest warned people to vaccinate their children Monday and worried that it could take months to contain the highly contagious viral illness due to a lower-than-normal vaccination rate at the epicenter of the crisis.
Health officials say the outbreak is a textbook example of why it's critical to vaccinate against measles, which was eradicated in the US after the vaccine was introduced in 1963.
In recent years, however, the viral illness has popped up again from New York to California and sickened hundreds.
Clark County, Washington, has a vaccination rate of 78 per cent, well below the level necessary to protect those with compromised immune systems or who can't get vaccinated because of medical issues or because they are too young.
Misinformation is circulating on social media, said Dr Alan Melnick, Clark County public health director.
"What keeps me up at night is eventually having a child die from this completely preventable situation," he said.
"It's still out there, even though it's been debunked, that the measles vaccine results in autism. That's nonsense."
Before mass vaccination, 400 to 500 people in the United States died of the measles every year, 50,000 people were hospitalized and 4,000 people developed brain swelling that can cause deafness, Melnick said.
One to three cases out of every 1,000 are fatal, he said.
People may have been exposed to the disease at about four dozen locations, including Portland International Airport and a Portland Trail Blazers game, officials said.
The vaccine has been part of routine childhood shots for decades, and measles was declared eliminated in the US in 2000. But measles is still a big problem in other parts of the world, and travellers infected abroad can bring the virus back and spread it, causing periodic outbreaks.
Last year, there were 17 outbreaks and about 350 cases of measles in the US.
Officials still are not sure where the Northwest outbreak began. The first known patient sought medical care on Dec. 31, but it isn't known if other people may have gotten sick before that and did not seek treatment.
Children receive the first vaccine between 12 and 15 months old and the second vaccine between ages 4 and 6. One vaccine provides 93 per cent immunity from measles, and two shots provide 97 per cent protection.
But the vaccine is less effective in those under a year old and is generally not given to infants.
The virus, spread by coughing or sneezing, can remain in the air for up to two hours in an isolated space.
Ninety per cent of people exposed to measles who have not been vaccinated will get it, health officials said.
Those who may have been exposed should watch for early symptoms of high fever, malaise and red eyes, followed by a rash that starts on the head and moves down the body.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)