The impact of immunization record aggregation on up-to-date rates-implications for immunization registries in rural areas

Problems with poorly documented immunization records may be especially impo rtant in rural areas. To evaluate the potential impact of a regional regist ry in a rural region, this study quantified the change in documented immuni zation rates for nine primary care sites in rural Colorado resulting from t he addition of public health department immunization clinic records. Manual chart reviews of immunization data were conducted at both private primary care and public health department sites in two geographic areas in rural Co lorado. Data front private primary care sites were matched to data front th e public health department sites. Immunization up-to-date (UTD) rates at ea ch primary care site were then recalculated for 12- and 24-month-olds after including data front public health department sites. Of 1,533 children, 46 9 (31 percent) were given immunizations at both a private primary care and a public health department site. The UTD rate (3:2:3:2) of 12-month-olds us ing only data front primary care sites ranged from 32 to 79 percent. Includ ing the public health department data increased the rates by 0 to 26 percen t (mean = 11 percent) for 12-month-old children. The UTD rate of 24-month-o lds (4:3:1:3 and any Hib on/after 12 months) ranged from 6 to 54 percent at the primary care sites. These rates increased by 6 to 21 percent (mean = 1 2 percent) when public health department data were added. This "virtual" re gistry combining primary care and public health department data increased c alculated immunization rates at primary care sites substantially, with a ra nge of 0 to 26 percent.