Current investigation - updated 4/29/2019
Clark County Public Health has declared the local measles outbreak over, after six weeks with no new cases.
Public Health confirmed 71 cases of measles during the months-long outbreak. Two confirmed cases previously included in the Clark County totals have been removed. Those two individuals moved to Georgia during the outbreak and are being counted in that state’s measles case numbers. The Clark County total does not include King County and Oregon cases that have been linked to the local outbreak.
The outbreak began Jan. 3, when laboratory testing confirmed measles in a child who traveled to Clark County from Ukraine. Based on the information gathered during the investigation, Public Health could not determine whether this case was the source of the outbreak.
The local outbreak predominantly affected children – 93 percent of cases were 1 to 18 years old – and people who were not immunized. One person was hospitalized.
Here are the details of the 71 confirmed cases:
- Age
- 1 to 10 years: 52 cases
- 11 to 18 years: 14 cases
- 19 to 29 years: one case
- 30 to 39 years: four cases
- Immunization status
- Unimmunized: 61 cases
- Unverified: seven cases
- 1 MMR vaccine: three cases
“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 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.”
Public Health identified 53 public sites where confirmed cases may have exposed others to the measles virus. Exposure sites included 13 health care facilities, 15 schools and child care centers, one workplace and 24 other public places, such as grocery stores, retail establishments and churches.
Based on Public Health’s investigation, the 71 confirmed cases most likely contracted measles within the household (51 percent); at a general public location, such as a grocery store, retail establishment or church (25 percent); or at a school or child care center (16 percent). One case (1 percent) was most likely exposed during international travel. Public Health could not determine the likely site of exposure for the remaining 7 percent of cases.
During the outbreak investigation, Public Health identified and contacted more than 4,100 people who were exposed to measles and made daily monitoring phone calls to more than 800 people considered susceptible to contracting measles. Local schools identified and excluded 849 susceptible students who were exposed to measles.
Immunoglobulin – antibodies that can help prevent measles infection – was administered to 44 infants, pregnant women and other children younger than 5 years old who were exposed to measles. Immunoglobulin must be administered within six days of exposure.
Public Health activated its incident management teams to respond to the measles outbreak on Jan. 15 and spent 63 days in incident response. More than 230 people worked on the incident, including 89 Public Health staff, 57 Washington Department of Health staff, 50 Medical Reserve Corps volunteers and three Centers for Disease Control and Prevention staff, as well as partners from other health departments and local volunteers.
Responders worked more than 19,000 hours on the measles outbreak, with Public Health staff clocking 12,684 hours on the outbreak. Public Health’s total cost for the outbreak is $864,679, with staffing costs accounting for the largest share ($616,265 for Public Health staff).
Investigation notes
During the outbreak, Public Health identified suspect cases who were unimmunized when exposed to measles and received the measles-mumps-rubella (MMR) vaccine more than 72 hours after exposure. To prevent illness, one dose of MMR vaccine must be given to unimmunized people within 72 hours of exposure.
About 5 percent of previously unvaccinated people will develop a rash after being immunized. When administered after 72 hours, the vaccine is less likely to prevent illness, and if the person develops a rash, there is a small chance that the rash is due to the vaccine. People who experience these mild vaccine-associated rashes cannot transmit the virus to other people.
However, in these situations, it is difficult to determine whether the rash is a benign vaccine reaction or measles illness. Specimens for these suspect cases were sent to a specialized laboratory out of state to confirm measles, but results can take more than a week. In those cases, pending lab results, Public Health treated the suspect cases as it would treat confirmed cases and released information about public locations the cases visited while potentially contagious with measles. Public Health removed those locations if the cases are ruled out.
On Feb. 12, Public Health removed one previously confirmed case after additional testing revealed the case was actually experiencing benign vaccine rash. That case – an unimmunized child 1 to 10 years old – received one dose of measles-mumps-rubella, or MMR. Public Health also removed the exposure locations associated with this case since the vaccine virus cannot be transmitted to others.
Clark County Council Chair Eileen Quiring declared on Friday, Jan. 18 a public health emergency in response to the measles outbreak. On Friday, Jan. 25, Gov. Jay Inslee declared a state of emergency in response to the measles outbreak in Washington.
Additional information
For information about measles cases in Oregon, visit the Oregon Health Authority measles webpage. For information about other measles cases in Washington, visit the Washington State Department of Health measles webpage.
For information about measles cases and outbreaks in the U.S., visit the Centers for Disease Control and Prevention website.
If you're unsure of your family's immunization status, you can view, download and print your family's immunization information online at MyIRmobile or request a copy of your immunization record from the Washington State Department of Health.
Anyone with questions about measles immunity or the measles vaccine should contact their primary care provider. Clark County Public Health does not provide immunizations or testing for immunity.
Anyone with questions about measles infection or the measles vaccine should call their primary care provider or their local county health department:
- Clark County Public Health, 564.397.8182
- Multnomah County Public Health, 503.988.3406
- Washington County Public Health, 503.846.3594
- Clackamas County Public Health, 503.655.8411