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Public Health confirmed 71 cases of measles during a months-long outbreak in 2019. 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, 2019, 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

Public Health declared the measles outbreak over on April 29, 2019, after six weeks with no new 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).

Children should receive two doses of the MMR (measles-mumps-rubella) vaccine. They should get the first dose at age 12 to 15 months and the second dose at age 4 to 6 years.

Adults born after 1956 should get at least one dose of MMR vaccine, unless they have other evidence of immunity (see below). Health care workers, college students and international travelers without other evidence of immunity should receive two appropriately spaced doses of MMR vaccine.

People are considered immune (not at risk) to measles if any of the following apply:

• They were born before 1957.
• They were diagnosed with measles in the past.
• They are up to date on measles vaccines (one dose for children 12 months through 3 years old, two doses for anyone 4 years and older).

After two doses, the MMR (measles-mumps-rubella) vaccine is 97% effective at preventing measles. That means three out of 100 people who get the vaccine may not make antibodies and may get measles. 

Vaccines, like medications, are not 100% effective. Some people’s immune system may not have responded well to the vaccine. But fully vaccinated people who get measles are more likely to have a milder illness and less likely to spread the disease to other people, especially those who can’t get vaccinated.

Yes, getting the MMR vaccine is much safer than getting infected with measles. The vaccine is constantly monitored for safety and effectiveness. The vaccine benefits outweigh any potential risks. Hundreds of millions of doses of the MMR vaccine have been given in the US since it was developed, with an excellent record of safety.

Measles can be a serious disease, with one in three people experiencing complications. Complications from measles are more common among children younger than 5, people over age 20, pregnant people, or those with weakened immune systems. 

The most common complication of measles include ear infections (1 in 10 children) and diarrhea (fewer than 1 in 10 people). Pneumonia (1 in 20 children) is the most common cause of measles-related death. About 1 out of 1,000 infected people will develop acute encephalitis (brain swelling) that can lead to permanent brain damage. Death from measles occurs in 1 to 3 per 1,000 people with measles in the United States.

The vaccine is made from a live virus, but it is weakened and cannot cause illness in people with healthy immune systems.  The weakened vaccine teaches your immune system to recognize the virus and develop immunity to it.

About 5% of people who receive the MMR vaccine develop a mild rash. When it occurs, the rash usually appears seven to 12 days after vaccination. This rash is not a measles infection and cannot be spread to others. The vaccine viruses are not spread from a vaccinated person, even if they develop a rash.

Very rarely people with weakened immune systems can develop vaccine-associated measles. That is why the vaccine is not recommended for some people who are severely immunocompromised.

In Clark County, 89.4% of students (K-12) were up to date on their measles vaccinations during the 2024-25 school year, according to the Washington State Department of Health. But the number of students who are vaccinated may actually be higher. 

During the 2024-25 school year, 7.1% of students were considered “out of compliance.” That means the school did not have documentation of their vaccination. Some of those students may be vaccinated but have not provided the school with the required documentation. 

Unvaccinated means the person has not received any doses of the MMR (measles-mumps-rubella) vaccine. 

A person’s vaccination status is considered “unknown” if they do not know if they were vaccinated and Public Health is unable to find any documentation of vaccination.