Immunization Survey－Yun Lin County
1986 Vol.2 NO.5
During the period January 27-30, an immunization survey was conducted among households in Yun Lin County to determine vaccination rates for children 12-23 months of age. Yun Lin, a predominantly rural county with one of the highest attack rates of polio during the 1982 epidemic1, was selected for the survey because vaccination rates might be low compared to other areas. To estimate vaccination rates with 95% confidence and ±10% accuracy, a minumum of 210 children 12-23 months of age were identified in 30 clusters of approximately 7 children per cluster2. A pilot survey in Yun Lin County determined that each cluster should contain about 100 households to find 7 children in the target age group. The number of households in each census tract was obtained from each township registration office, and adjacent census tracts were grouped into clusters of approximately 100 households each. From these, 30 clusters were randomly selected for the survey. Interviewers visited all households in each cluster; households in which no one was home were revisited until all interviews were complete. Only children who lived in the household were included in the survey; those registered but who lived at other addresses were excluded. Vaccinations counted were those verified by government immunization card, or by health station or private medical record. Children counted as completely immunized were those who received all of the following vaccines: one dose of BCG, three doses of DPT and polio, and one dose of measles.