LB-20. Minnesota Measles Outbreak, 2011
Session: Poster Abstract Session: Late Breaker Posters
Saturday, October 22, 2011
Room: Poster Hall B1
Background: Endemic measles transmission in the US was eliminated in 2000. From January to July 2011, 174 US cases were reported - the highest number since 1996. On March 2, 2011, measles was confirmed in a 9 mo. MN child with no known exposure who resided in a Hennepin County (HC) homeless shelter. In the subsequent 9 weeks, 22 measles cases were confirmed in HC; 21 were part of an outbreak. Per the MN immunization registry, MMR rates have dropped among children of Somali descent in HC (at least 1 MMR at 24 mo. was 84% among those born in 2007 and 57% in 2009; it was 84% and 85% in non-Somali children).

Method: Cases were interviewed for exposures and contacts. Post-exposure prophylaxis was administered to susceptible, eligible contacts, and voluntary quarantine was advised. Also, MMR was recommended for  > 6 mo. in homeless shelters in HC; catch up vaccination (with second dose after 28 days) was recommended in HC and for the local Somali community. Community meetings and vaccination clinics were held.

Result: Contact tracing found an unvaccinated US born 30 mo. child of Somali descent with recent travel to Kenya and rash onset 1 day after attending a drop-in childcare center (CC). Measles developed in 3 contacts at CC (including first case) and 1 household contact. Subsequent cases occurred in 2 homeless shelters (n=8), 2 healthcare facilities (n=3), 2 households (n=3), 1 other CC (n=1); exposure unknown (n=1). 7 cases were too young for vaccine (2 of Somali descent), 9 of age but not vaccinated (8 due to safety concerns, 6 of Somali descent), 1 vaccinated <12 mo., 4 had unknown vaccination. Median age of cases was 1 y (range 4 mo.-51 y). 14 (ages 7 mo. -11 y) were hospitalized (mean 5 days; range 2-7). 71 doses of IG were given and 9 community vaccination clinics were held.

Conclusion: Ongoing transmission of measles in MN occurred primarily because of low vaccination rates in a specific community, and exposures in homeless shelters. These issues occur in other US communities, putting them at a risk for outbreaks if measles is introduced from areas with high disease rates. A high hospitalization rate in children reinforces that measles may not be benign. Healthcare provider communication with parents about vaccine safety and measles infection must be re-evaluated and improved.

Subject Category: I. Adult and Pediatric Vaccines

Pamala Gahr, MPH1, Aaron DeVries, MD, MPH1, Cynthia Kenyon, MPH1, Erica Bagstad, MS, MPH2, David Boxrud, MS1, Karen White, MPH1 and Ruth Lynfield, MD1, (1)Minnesota Department of Health, St. Paul, MN, (2)Hennepin County Human Services and Public Health, Hopkins, MN


P. Gahr, None

A. DeVries, None

C. Kenyon, None

E. Bagstad, None

D. Boxrud, None

K. White, None

R. Lynfield, None

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