TABLE 2

Spatial Clusters of Underimmunization by Time Period, Kaiser Permanente Northern California

Time PeriodCluster Number and General DescriptionRadius, kmBlock Groups in Cluster, nUnderimmunized Children in Cluster, %aExpected Underimmunized Cases, nActual Underimmunized Cases, nRRP
2010–20121: East Bay, Richmond to San Leandro1462718.84276501.58<.001
2: Sonoma and Napa4754817.54866901.47<.001
3: Eastern Sacramento926217.51962781.44<.001
4: Northern San Francisco and southern Marin counties1623518.11091601.48.023
5: Vallejo33822.735641.85.042
2006–20091: El Cerrito to Downtown Oakland619719.7891912.18<.001
2: Stockton to Merced6772413.14906971.48<.001
3: Western Sonoma224630.311373.30<.001
4: Southeastern Oakland24419.633702.13<.001
5: Vallejo57114.4851331.57.013
2002–20051: Eastern Sacramento1446712.22333501.56<.001
2: San Francisco and East Bay1153012.91071701.61<.001
3: Stockton to Fresno201110210.72633451.35.011
4: Santa Clara22022.710272.81.039
  • a The percent of children outside of the clusters who were underimmunized was 10.9% in 2010–2012, 8.4% in 2006–2009, and 7.3% in 2003–2005.