The measles outbreak concentrated in Southwest Washington state has been declared over after six weeks of no new cases, public-health officials say.
The outbreak, with 71 confirmed cases in Clark County, began Jan. 3 when laboratory testing confirmed measles in a child who traveled to Clark County from Ukraine. Officials never determined whether this case was the source of the outbreak, according to a Public Health news release. One case was reported in King County.
Nearly all cases were in children — 93% involved patients between the ages of 1 and 18 — and people who were not immunized. One person was hospitalized, according to Clark County Public Health.
“We’re grateful to see this outbreak come to an end without any deaths or serious complications,” Dr. Alan Melnick, Clark County health officer and Public Health director said in a news release. “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.”
The outbreak previously had 73 confirmed cases, but the number was revised after two people moved to Georgia; their cases are now being counted there.
The end date was decided upon by Public Health, the Washington Department of Health, and the Centers for Disease Control and Prevention, Melnick explained at a Clark County Board of Health meeting Wednesday.
Melnick said the state and CDC were fine with the end date being April 24. However, Melnick said he wanted to count 42 days — or two incubation periods — from four days after rash onset, or the last day the last confirmed case was contagious, which was March 17. The CDC and state suggested counting from the first day of rash onset, before agreeing with Melnick’s proposal.
Measles is extremely contagious and was declared eradicated in the United States in 2000 but has come roaring back in recent years in the U.S. and around the globe.
There have been 704 cases in 22 states this year. That count includes 44 people who caught the disease while traveling in another country, according to the Centers for Disease Control and Prevention. Some of them triggered U.S. outbreaks, mostly among unvaccinated people, including large outbreaks in Orthodox Jewish communities in and around New York City.
In response to the measles outbreak, the Washington State Legislature moved to tighten up exemptions for the measles, mumps, and rubella (MMR) vaccination. The bill that eliminates parents from exempting their children from the MMR vaccine based on personal or philosophical reasons passed the House and Senate and is waiting to be signed by Gov. Jay Inslee.
Communities are safest from a measles outbreak when at least 95% of the population is immunized. This threshold is called herd immunity. In Clark County, 85% of kindergartners had the measles-mumps-rubella (MMR) vaccine.
Dr. Jeffery Duchin, a health officer with Public Health – Seattle & King County, said outbreaks will continue to pop up because travelers to a lot of places in the U.S. and around the world will come in contact with measles. To combat outbreaks in King County, Duchin said, Public Health will continue educating the public about the importance and safety of vaccinations.
One of the more successful programs for increasing vaccination rates was a partnership with the Somali Health Board (SHB). King County and the SHB tailored messaging about vaccinations to the Somali community by publicizing photos of imams being vaccinated and creating a comic strip explaining why vaccinations work and why they are important.
Duchin said Public Health is replicating this work with other health boards that serve specific communities.
Clark County’s public-health staff worked a combined 12,684 hours on the outbreak, which cost the county $864,679, according to a news release.
Information from The Associated Press was included in this report.