Which method is NOT typically used to measure immunization coverage?

• A. Immunization registries
• B. Blood antibody titers
• C. Administrative data
• D. Surveys

Answer: (B)

Measuring immunization coverage is about estimating how many people in a population have received a vaccine, using systems that track vaccines or survey records. Administrative data tallies doses given and compares them to the population in need, immunization registries hold individual vaccination histories to show who is up to date, and surveys verify vaccination status through cards or caregiver recall with representative sampling. These approaches are practical, scalable, and able to produce population-level estimates.

Blood antibody titers, on the other hand, are not typically used to measure coverage because they are invasive and costly to collect, require lab testing, and are not a straightforward proxy for vaccination status. Antibody levels can be influenced by waning immunity, prior infections, or responses that don’t perfectly reflect protection for all vaccines. They’re more useful for assessing immunity in specific individuals or groups or for research/validation in targeted settings, rather than as a routine method to gauge overall vaccination coverage across a population.