Outbreak of Measles in a Community with Low Vaccination Coverage in Two Kansas Counties – 2014

BACKGROUND: Through vaccination and control efforts the United States declared endemic measles as eliminated in 2000; imported cases of measles continue and can lead to outbreaks, especially in communities with low vaccination coverage.  In June, 2014 Johnson County Health Department (JOHD), in Eastern Kansas, notified the Kansas Department of Health and Environment of two persons symptomatic with measles with exposure to an ongoing measles outbreak in a neighboring state.  An investigation was initiated and ongoing when two additional persons with symptoms of measles were reported from Sedgwick County Health Department (SGHD) located in South-Central Kansas. 

METHODS: Investigations included current and retrospective case finding. Persons were interviewed in person using a standardized questionnaire. Cases were classified according to CSTE case definition. Contacts were notified of their exposure. Unvaccinated contacts were offered MMR vaccine or immunoglobulin (IG). Serology, polymerase chain reaction, and genotyping were performed.

RESULTS: Fourteen persons with confirmed cases of measles were identified.  Persons from both counties had frequently visited households in another state where measles transmission was occurring.  Illness onset ranged from May to July 2014. Seven persons were unvaccinated, six were not aware of their vaccination status, and one was fully vaccinated.  Susceptible household contacts were quarantined for 21 days following their last exposure and daily checks at each household were conducted by local health departments.  In addition, the local health officer at Sedgwick County served two written orders for quarantine. IG was administered to 11 persons and 452 persons were given MMR vaccine by the SGHD. Possible places of exposure included three hospitals, two clinics, two restaurants, a daycare, hotel, and softball tournament. All contacts at these locations were either contacted by letter or telephone and where specific individuals couldn’t be identified, press releases were distributed.  Documented transmission occurred at both restaurants and softball tournament. Twelve specimens were positive by either PCR or serology and the genotype was B3 which was consistent with the endemic measles strain circulating in the country where the index case had just traveled.  

CONCLUSIONS: From May through July 2014, 14 persons all associated with a multistate outbreak were diagnosed with measles in Kansas, more than any year since 1991.  In-person interviews were helpful in identifying places where others may have been exposed.  Even though daily checks were conducted and quarantines were implemented, non-compliance within this community likely resulted in additional transmission of measles. However, rapid interventions by public health were instrumental in preventing further transmission.