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

Figures & data

Table 1. Proposed standardized definitions of vaccination indicators.

	Definition
Terminology	Referring to an individual	Referring to a population
Vaccine coverage	N/A	The proportion of the target (or accessible) population that received the specified number of vaccine doses. It is important for researchers to specify the nature of the target population, eg., all persons in a specific population who are in the age group, vs. only those persons in the age group who meet eligibility criteria according to the named and specific recommending body.
Vaccine uptake	The behavior of accepting a vaccine.	The number of people who received a specified vaccine dose(s).
Vaccination rate	N/A	The proportion of the target (or accessible) population that received the specified number of vaccine doses, within a specific timeframe.
Vaccination status	Receipt of vaccines categorized as non-vaccinated, vaccine series initiated, vaccine series completed, partially or incompletely vaccinated.	The proportion of the target population that have achieved the designated category.
Vaccine series initiation	Receipt of the first dose in a specified vaccine series. It is important to specify whether the denominator is all eligible individuals, or only those that initiated the series.	The proportion of the target population that have received the first dose in a specified vaccine series.
Vaccine series completion	Receipt of all recommended doses for a particular vaccine series (should specify who makes the recommendation and what the recommended series consists of).	The proportion of the target population that have received all recommended doses for a particular vaccine series.
Completely/Fully vaccinated	Receipt of all vaccines recommended by a certain age (should specify who makes the recommendation and what the recommended schedule consists of).	The proportion of the target population that have received all vaccines recommended by a certain age.
Up-to-date vaccination	Receipt of the recommended number of vaccine doses by a specified age, whether or not it was all doses required for series completion.	The proportion of the target population that have received the recommended number of vaccine doses by a specified age, whether or not it was all doses required for the series.
Timely vaccination	Receipt of specified vaccines within a time-limited period following the age at which it was due (most commonly, within 1 month of scheduled date). The age it is due and the lag time being applied should be specified.	The proportion of the target population that have received specified vaccines a time-limited period following the age at which it was due.
Partial vaccination or incomplete vaccination (there is no clear consensus on which term to use)	When referring to a multi-dose vaccine: Receipt of less than all required vaccine doses for a vaccine series. When referring to an entire vaccine schedule: Receipt of less than all required vaccine doses in the vaccine schedule.	The proportion of the target population that have received less than all required vaccine doses for a vaccine series or less than all required vaccine doses in the vaccine schedule.
Non-vaccination	No receipt of specified vaccine(s). If possible, researchers should specify if this includes individuals non-vaccinated for legitimate reasons, such as medical contraindication.	The proportion of the target population that have not received the specified vaccine(s).