Health Literacy about Vaccination of adults in ITalian

Domains assessed: Prose: Comprehension, Information seeking: Interactive media navigation, Information seeking: Document, Comprehension

Specific context: Vaccination, Infectious Disease, Health Promotion

Validation sample population age: Older Adults: 65+ years, Adults: 18 to 64 years

Modes of administration in validation study: Paper and pencil

Number of items: 14

Sample size in validation study: 200

Administration Time (minutes): 5 minutes

Language of validated version: Italian

Categorical scoring: Yes

Scoring categories: HLVa-IT is composed of 14 items (questions) divided into three scales: functional Vaccine Literacy (VL) (items number 1 to 5); interactive, also called communicative VL (items number 6 to 10); critical VL (items number 11 to 14). From the psychometric point of view, functional VL questions are more about language capabilities, involving the semantic system, while the interactive/ critical questions regard more the cognitive efforts, such as problem solving and decision making. The answers are supplied by the interviewee according to a Likert scale with four possible choices: 4-never, 3-rarely, 2-sometimes, 1-often, for the functional scale; 1-never, 2-rarely, 3-sometimes, 4-often, for the interactive and critical scale. The score is obtained from the mean value of the answers to each scale, and is comprised between 1 and 4: a higher value corresponds to a higher Vaccine Literacy level.

Country where validated: Italy

Content validity: Face (content) validity has been carried out with the aim of validating the apparent and external significance of HLVa-IT, through the judgement of the items provided for in the test, by a panel of experts in the vaccination field and public health.

Reliability (Cronbach Alpha): 0.816

Reliability notes: Cronbach’s alfa was calculated on the answers to the questions of each of the HLVa-IT scales, functional (α=0.8157), interactive (α=0.8814) and critical (α=0.9021), as well as on interactive/critical (α=0.9369). Inter-item correlation coefficients were significant for all pairs of questions. Principal Component Analysis identified two main factors representing 62.70% of the total variability: all Items of the interactive/critical scale loaded on the first factor (eigenvalue =5.81), while those of the functional scale on the other factor (eigenvalue =2.97), confirming that interactive and critical scales belong to the same domain.