Are we speaking the same language? an argument for the consistent use of terminology and definitions for childhood vaccination indicators

Abstract

Vaccination indicators are used to measure the health status of individuals or populations and to evaluate the effectiveness of vaccination programs or policies. Ensuring that vaccination indicators are clearly and consistently defined is important for effective communication of outcomes, accurate program evaluation, and comparison between different populations, times, and contexts. The purpose of this commentary is to describe commonly used vaccination indicators and to highlight inconsistencies in how childhood vaccine researchers use and define these terms. The indicators we describe are vaccine coverage, uptake, and rate; vaccination status, initiation, and completion; and up-to-date, timely, partial, and incomplete vaccination. We conclude that many vaccination indicators are not explicitly defined within published research studies and/or are used quite differently across studies. We also note that the choice of indicator in a given study is often driven by program or vaccine specific factors, may be constrained by data availability, and should be chosen to best reflect the outcome of interest. We conclude that the use of consistent language and definitions would promote more effective communication of research findings. We also propose some standardized definitions for common indicators, with the goal of provoking discussion and debate on the issue.

Redefining vaccination coverage and timeliness measures using electronic immunization registry data in low- and middle-income countries

“…Below we define and describe commonly used measures amongst LMICs to provide background on how these measures can be improved using individual-level data from EIRs, recognizing that terminology is often used inconsistently by immunization experts [20] .…”

“…Traditionally timeliness refers to whether a child receives a vaccine within a specific timeframe, where they can receive a dose early, on-time, or late. An up-to-date vaccination schedule is generally based on whether all recommended vaccines were administered before a particular age or point in time [20] . Historically dose validity has not been incorporated into performance measures, except for surveys; for aggregate RHIS data in LMICs, doses are counted if they are administered, regardless of their timing.…”

Determinants of self-paid rotavirus vaccination status in Kanazawa, Japan, including socioeconomic factors, parents’ perception, and children’s characteristics

“…Ensuring that vaccination indicators (such as vaccine coverage and uptake) are clearly and consistently defined is important for effective communication of outcomes [28]. According to the US Centers for Disease Control and Prevention, childhood vaccination coverage is defined as the percentage of children in the target population who received a dose of a recommended vaccine [29].…”

Determinants of self-paid rotavirus vaccination status in Kanazawa, Japan, including socioeconomic factors, parents’ perception, and children’s characteristics

“…Ensuring that vaccination indicators (such as vaccine coverage and uptake) are clearly and consistently de ned is important for effective communication of outcomes. 28) According to the US Centers for Disease Control and Prevention, childhood vaccination coverage is de ned as the percentage of children in the target population who received a dose of a recommended vaccine. 29) Vaccine uptake is most commonly de ned as the absolute number of people who received a speci c dose; that is, the numerator in the vaccine coverage calculation.…”