The Clark County, Washington, measles outbreak is officially over, public health authorities announced on Monday.
That marks 42 days — two cycles of a measles infection — without a new case. The largest outbreak in the Northwest since measles was eliminated in 2000 and one of the largest in the country during a year of record-setting measles cases, the outbreak cost public health authorities nearly $1 million and lasted 75 days.
Between Washington state and Oregon, 77 people got sick. The outbreak also forced schools to exclude unvaccinated students and teachers, disrupted local business in the Vancouver area and prompted a public health emergency declaration in Washington state.
Measles is a highly contagious virus that spreads through the air and can linger for up to two hours in an enclosed area. Nine out of 10 unvaccinated people who are exposed to the virus will contract it, according to the federal Centers for Disease Control and Prevention. For every 1,000 people who get measles, one to two die.
The outbreak also included two people infected in Clark County who moved to Georgia and a Vancouver-area resident who was sequestered in Hawaii when her symptoms started to show.
But the bulk of the cases were concentrated in the Vancouver area, which had 71 cases. About 93% of those cases were in children under 18 years old. The majority of those were younger than 10.
Nearly all were completely unvaccinated.
One person was hospitalized during the outbreak.
The outbreak began when an unvaccinated child brought measles to Clark County from Ukraine, which is in the midst of the largest global measles outbreak due to low vaccination rates.
Public health officials have not determined whether that child was the one who brought measles to Clark County and set off all the other cases and officials say that they might never know.
“We’re grateful to see this outbreak come to an end without any deaths or serious complications,” said Dr. Alan Melnick, Clark County health officer and public health department director. “But as long as measles exists elsewhere in the world and people continue travel, we’re at risk of seeing another outbreak. We must improve our immunization rates to prevent future outbreaks and keep our children and other vulnerable people safe.”
Melnick has been outspoken about the need to raise vaccination rates in Washington, and especially Clark County.
The misinformation that has fueled the decline in vaccination rates, largely born from a debunked assertion that vaccines cause autism, seems to be as contagious as measles itself.
Washington will soon have a law that eliminates all but medical exemptions to the measles, mumps and rubella vaccine for all school-age children who want to attend school. Oregon is considering a broader bill that would do the same for all vaccines.
House Bill 3063 would eliminate all exemptions to vaccinations for school-age children, except for medical reasons. Parents who choose not to vaccinate their child would have to enroll them in online or home school.
Here are some statistics Clark County Public Health released about the outbreak:
• About 51% of people who contracted measles got it within their household — meaning from a family member.
• 25% got measles from a public location, such as a grocery store, retail shop or church. Measles is spread through the air and can linger in an enclosed place for up to two hours, making an infected person in a high-trafficked place a particularly dangerous risk.
• 16% got measles from a school or child care center.
• Public health officials cannot determine where 7% of the cases came from, but said they all had the same wild European strain of measles, indicating they were linked.
• 4,100 people were identified as being exposed to measles during the course of the outbreak.
• More than 800 people received daily calls from Clark County Public Health to monitor whether their exposure turned into measles.
• Clark County schools excluded 849 unvaccinated students from school so they wouldn’t catch or spread measles
• Health officials gave immunoglobulin — antibodies that can help prevent measles for someone who has been exposed to the virus — to 44 infants, pregnant women and children under 5 years old. Immunoglobulin is one of the last lines of defense for someone who is vulnerable to infection and has been exposed to measles. Receiving the MMR vaccine is another way to stave off measles, but both most be given within a week of exposure.
• Clark County Public Health activated its emergency response teams to the measles outbreak on Jan. 15 — about two weeks after the first case. From there, the agency was in response mode for 63 days.
• More than 230 people from across the state worked on the outbreak. Gov. Jay Inslee declared a public emergency so that workers from other agencies and other states could lend resources to the response. That included 89 staff from Clark County Public Health, 57 people from the Washington Department of Health, 50 Medical Reserve Corps volunteers and three federal workers from the Centers for Disease Control and Prevention.
• These responders worked more than 19,000 hours on the outbreak — 12,684 of those of Clark County Public Health staff.
• The final bill for Clark County Public Health came to $864,679. Staffing made up more than three-fourths of that. The state surpassed $1 million total in February.