An Outbreak of Measles in an Undervaccinated Community

Abstract

Measles is readily spread to susceptible individuals, but is no longer endemic in the United States. In March 2011, measles was confirmed in a Minnesota child without travel abroad. This was the first identified case-patient of an outbreak. An investigation was initiated to determine the source, prevent transmission, and examine measles-mumpsrubella (MMR) vaccine coverage in the affected community. Investigation and response included case-patient follow-up, post-exposure prophylaxis, voluntary isolation and quarantine, and early MMR vaccine for non-immune shelter residents .6 months and ,12 months of age. Vaccine coverage was assessed by using immunization information system records. Outreach to the affected community included education and support from public health, health care, and community and spiritual leaders. Twenty-one measles cases were identified. The median age was 12 months (range, 4 months to 51 years) and 14 (67%) were hospitalized (range of stay, 2-7 days). The source was a 30-monthold US-born child of Somali descent infected while visiting Kenya. Measles spread in several settings, and over 3000 individuals were exposed. Sixteen case-patients were unvaccinated; 9 of the 16 were age-eligible: 7 of the 9 had safety concerns and 6 were of Somali descent.

Public health responses during measles outbreaks in elimination settings: Strategies and challenges

“…Much can be learned from measles outbreaks, especially in describing pockets of under-immunized people that may require targeted preventive efforts, 27 and in documenting response strategies that were successful in limiting measles spread. Data from elimination settings indicate that the characteristics of unvaccinated populations are diverse; they may be faith-based groups, 12 ethnic subpopulations, 14 , 28 and certain age-cohorts 29 or members of a socioeconomic strata 30 that experienced lower immunization coverage historically. As such, preventive and response measures should be tailored to each population to be effective.…”

“…Such analysis can be strengthened greatly by having both numerator and denominator data on the number vaccinated. This enables coverage to be calculated for specific communities, such as groups that are under vaccinated due to religious or philosophical reasons, 14 and efforts should be made to develop such data as these data are not widely available. Costs incurred by the public health sector during the response, or even a full economic evaluation, are also of interest.…”

“…11 , 12 , 14 , 30 , 48-50 Limited evidence suggests that using quarantine for non-immune close contacts of cases may considerably reduce the number of secondary cases from these contacts. During an outbreak in Geneva, an 18-day quarantine recommendation resulted in 6 secondary cases from 50 quarantined cases, compared to 81 secondary cases from 173 non-quarantined cases (relative risk: 0.26; 95% CI: 0.06–0.65).…”

“…The quarantine of individuals living in homeless shelters or communal living facilities presents an additional challenge to health authorities, as shared living spaces make quarantine compliance nearly impossible. 14 In certain circumstances, enforcing quarantine may be counterproductive, in that it may discourage disease reporting and erode public confidence.…”

Parental Country of Birth and Childhood Vaccination Uptake in Washington State

“…One study in Minnesota revealed that measlesmumps-rubella (MMR) vaccination coverage in Somali children was initially greater than in non-Somali children but subsequently declined (from 91% in 2004 to 54% in 2010) and was much lower than in nonSomali children by the end of the study period. 4 This decline was attributed to the perceptions in the Somali community that SomaliAmerican children have high rates of autism and that the MMR vaccine causes autism. [4][5][6] This decline in MMR vaccination uptake among Somali children was associated with a large measles outbreak in Minnesota.…”