Clark County’s measles outbreak of 71 confirmed cases was declared over by Clark County Public Health Monday, after six weeks elapsed with no new confirmed cases.
The outbreak required two incubation periods, or 42 days, with no new cases before Clark County Public Health Director Dr. Alan Melnick would declare it over. The last confirmed case was March 18.
The first confirmed case came through testing on Jan. 3 of a child who traveled to Clark County from Ukraine. Public Health’s investigation was never able to determine whether that case sparked the outbreak, according to a Public Health news release.
There had been 73 confirmed cases, but two patients moved to the state of Georgia during the outbreak, and will now count toward Georgia’s caseload. Clark County’s outbreak doesn’t include one case in King County and four in Multnomah County that were linked to Clark County’s outbreak.
The outbreak cost Public Health $864,679, but $80,000 of that is covered by grant funds, and the state Legislature has appropriated $744,000 to reimburse the county for outbreak response. Melnick said Clark County’s out-of-pocket cost should be around $40,000.
Of the 71 patients, 61 were not immunized. Seven others’ immunization statuses were unable to be verified and three patients had received only one of the two recommended doses of the measles, mumps and rubella vaccine.
There were 52 cases between the ages of 1 to 10 years old; 14 cases between 11 to 18; one case between 19 to 29; and four cases between 30 to 39. One person was hospitalized during the outbreak and recovered without major medical complications, Melnick has previously said.
Immunoglobulin are antibodies that can help prevent the measles infection if administered within six days of exposure. Public Health administered immunoglobulin to 44 infants, pregnant women and other children younger than 5 who were exposed to the virus during the outbreak.
“Those are the people who need to be protected through herd immunity. Pregnant women, infants, people with immunosuppression,” Melnick said. “They’re not eligible for the vaccine. Don’t just immunize your child or yourself to protect your child or yourself, but immunize them to protect everybody around you. In the anti-vaccination movement, there’s this big thing around personal freedom and choice to get vaccinated, but what about the personal choice of a parent who has an immunosuppressed child in school? They want to be able to feel that school is a safe place for their child to be.”
Public Health identified 53 public sites where confirmed cases may have exposed the measles virus to others: 13 health care facilities, 15 schools and child care centers, one workplace and 24 others public gathering spots such as stores and churches.
There were 849 non-immunized students excluded from schools due to the outbreak.
Public Health’s investigation discovered that 51 percent of the patients most likely contracted measles from another person in their home, while 25 percent likely contracted measles at a public location. Sixteen percent likely contracted the virus at a school or child care center.
Only one case was likely linked to international travel, and Public Health could not determine likely exposure sites for 7 percent of cases.
Public Health activated incident management teams on Jan. 15 to bolster its response to the outbreak, and during the investigation Public Health identified and contacted more than 4,100 people who were possibly exposed.
Incident response stayed in place for 63 days, and more than 230 people worked on the outbreak. The bulk of that work came from Public Health, who had 89 staffers work on response. The Washington Department of Health (57 staffers), Medical Reserve Corps (50 volunteers) and the Centers for Disease Control and Prevention (three staffers) also worked on response.
Responders put in more than 19,000 hours, with Public Health employees accounting for 12,684 hours. Staffing costs for the outbreak were $616,265. There were more than 800 daily monitoring calls made to people who were considered susceptible to contracting measles.
Melnick said House Bill 1638, which will eliminate personal exemptions for the measles, mumps and rubella vaccination for school children, should raise MMR vaccination rates across the state. But Melnick said people should still be watchful of complacency surrounding overall vaccination rates. State data backs up his concerns.
During the fourth week of this year, at the peak of the outbreak, there were 1,078 vaccines administered to minors in Clark County. That was about 800 more than the same week last year.
The following week, 1,023 vaccines were administered to minors, also about 800 more than last year. In week nine of this year, that number dropped to 319 vaccinations administered — about 125 more than last year, but less than the thousands being administered earlier this year.
“I was a bit gratified in January and February when more people were getting vaccinated,” Melnick said. “The problem is that those numbers dropped off. I remain concerned that complacency is going to hit and people will forget what happened and immunization rates will drop. Having an outbreak is a lousy way to get immunization rates up.”