Abstract
Dear Editor,
Vaccine uptake may be negatively impacted through poor patient health literacy. 1 Health literacy, the ability to understand and act on health information, is one of the most pressing issues in healthcare today. 2 By improving vaccine health literacy in patients, we create opportunities to drive up vaccine uptake. Readability of health-related materials that the patient is expected to read can now be measured quantitatively through several indices, scores, and algorithms, to help calibrate the reading level of health texts. 3
In the United States, there are numerous sources of information on vaccines for recipients, carers, and family on vaccine-preventable infectious diseases from federal, state, pharmaceutical, and charitable organisations. While the FDA produces vaccine package inserts, which are for healthcare professional, patient-facing information is formally given in the Vaccine Information Statement (VIS). A VIS is a document, produced by the CDC, that informs vaccine recipients, or their parents or legal representatives, about the benefits and risks of a vaccine they are receiving. All vaccine providers, public or private, are required by the National Vaccine Childhood Injury Act to give the appropriate VIS to the patient (or parent or legal representative) prior to every dose of specific vaccines. 1 The U.S. Department for Health & Human Services (HHS) also offers patients a dedicated website on vaccine information (www.vaccines.gov).
It was therefore the aim of this study to compare the readability of patient-facing vaccine information materials, as provided by Vaccine Information Statements (CDC) and the U.S. Department of Health & Human Services (www.vaccines.gov).
Patient-facing information documents for vaccine recipients, patients, and carers were sourced from Vaccine Information Statements (CDC) (https://www.cdc.gov/vaccines/hcp/vis/index.html) and the U.S. Department of Health & Human Services (HHS) website “Vaccines by Disease” (www.vaccines.gov). Vaccine information from 23 vaccine-preventable infectious diseases were extracted and analysed, as shown (Tables 1 and 2). Information from these sources were copied and pasted into the subscription-based Readability (ContentPro) calculator (www.readable.com) and a readability assessment carried out examining 10 readability metrics, in accordance with the software instuctions. Calculated readability parameters for each of the vaccines are shown in Table 1 (VIS) and Table 2 (HHS).
Readability scores of 23 vaccines as published in Vaccine Information Statements (VIS).
HPV, human papillomavirus; VIS, Vaccine Information Statements.
Readability scores of 23 vaccines as published by U.S. Department of Health & Human Services (HHS).
HPV, human papillomavirus.
Of the 10 metrics examined, four of these parameters (Number of words, Number of sentences, Words per sentence, and Syllables per word) were absolute measurements, whereas the remaining six metrics were calculated parameters. Readability can be quantified by several metrics, of which the Flesch Reading Ease is the most commonly used. This metric gives a score of 0–100, with 0 being unreadable and 100 being most readable. It is based on the average number of syllables per word and the average number of words per sentence. Scoring between 70 and 80 is equivalent to school grade level 8 and college graduates can understand documents with a score of 0–30. This means text with a score of 60–70 should be fairly easy for the average adult to read. This index is commonly used by marketers, research communicators, and policy writers, which helps them assess the ease by which a piece of text will be understood and engaged with by their readership. A derivative of the Flesch Reading Ease score is the Flesch–Kincaid Grade Level index, which is a widely used readability formula which assesses the approximate reading grade level of a text. If a text has a Flesch–Kincaid Grade Level level of 8, this means the reader needs a grade 8 level of reading or above to understand it. Further interpretive criteria on the Gunning-Fog and SMOG indices are available. 3
When applied to patient-facing vaccine literature, we can see that VIS information was significantly less easy to read than HHS information, as supported by the Flesch Reading Ease, Flesch–Kincaid Grade Leve, Gunning–Fog, and SMOG parameters. Furthermore, the HHS materials employed less words per sentence and less syllables per word than the VIS information.
The last 50 years has seen the steady evolution of guidelines, laws, and requirements, all supporting the use of plain language, culminating in the Plain Writing Act of 2010. Adoption of plain language approaches to scientific and medical communication will further support patients in their understanding of the background, diagnosis, and treatment of their disease conditions. The availability of free and subscription-based readability calculators now allow a simple and effective way to quantitatively measure and correct written text and web-based resources for the benefit of patients.
Readability addresses functional health literacy, through improving communication of information to patients and service users. Nutbeam’s Model of Health Literacy defines three components of Health Literacy, namely Functional Health Literacy, Interactive Health Literacy, and Critical Health Literacy. 4 With Functional Health Literacy, the transmission of easy-to-read materials on health risks and health service utilisation leads to improved knowledge for the individual, as well as increased participation in population health programmes, including vaccination. 4 Further work is now required to investigate the importance of readability in achieving optimal Funtional Health Literacy.
In conclusion, preparation of patient-facing materials of a complex topic, such as describing vaccines, is difficult to accomplish successfully. Adoption of readability calculators and scrutiny of materials of their readability will help authors develop materials with improved understanding for vaccine recipients, carers, and family, potentially leading to improved health literacy and vaccine uptake.
Footnotes
Conflict of interest statement
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethical statement
This article does not contain any studies with human participants or animals performed by any of the authors.
Data availability statement
All data relevant to the study are included in the article.