Clark County has declared a public health emergency in the wake of a measles outbreak that has sickened at least 19 people, 18 of them children.

Clark County Council Chair Eileen Quiring declared the emergency Friday, the same day that the list of sites linked to the outbreak included a Jan. 11 Trail Blazers game at Portland’s Moda Center attended by 19,000 people.

According to a news release by the county, the declaration allows the county to have access to additional resources outside the regional area.

Eighteen Clark County-area children and one adult have the preventable disease, public health officials have confirmed, and seven more are suspected of having it. Sixteen of the confirmed cases are in people who haven’t been vaccinated.

Measles is a highly contagious viral illness spread through the air when an infected person coughs or sneezes. It was thought to be eradicated years after the vaccine hit the U.S. in 1963. Prior to the vaccine, 400 to 500 people would die every year, and 48,000 or more were hospitalized.

Clark County has one of the worst vaccination rates among all Washington counties, with just 77.4 percent of all public students having completed their vaccinations, according to state records.

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