[A sampling plan for evaluation of vaccinal coverage]

Area of Science:

• Epidemiology
• Public Health
• Biostatistics

Context:

• Estimating vaccination coverage is crucial for public health planning and disease prevention.
• The 1983 survey in Araraquara County, Brazil, aimed to assess immunization rates in young children.
• The study targeted children aged 12-13 months, a key demographic for childhood immunizations.

Purpose:

• To describe a sampling project designed to estimate vaccination coverage in Araraquara County.
• To detail the application of R.H. Henderson and T. Sundaresan's method for the Expanded Programme on Immunization (EPI).
• To present the ratio-estimate as the estimator for vaccination coverage rate and its standard error calculation.

Summary:

• A stratified sampling approach was used, dividing the target population into children in private and collective dwellings.
• R.H. Henderson and T. Sundaresan's method, adapted for urban and rural zones, involved probability proportional to size selection of areas, blocks, and households.
• A sample was drawn from both strata using the same sampling fraction, with a ratio-estimate proposed for coverage rate calculation.

Impact:

• The described methodology provides a framework for conducting similar vaccination coverage surveys in other regions.
• Accurate estimation of vaccination coverage is essential for identifying immunization gaps and informing public health interventions.
• The study contributes to the understanding of sampling techniques applicable to immunization programs in developing countries.