Readability of COVID-19 vaccine information for the general public



Mayo Vaccine Research Group, Mayo Clinic, Rochester, MN, USA

Luke S. Bothun, Scott E. Feeder, Gregory A. Poland


Question: Are the readability levels for COVID-19 vaccine-related fact sheets and informational materials appropriate for the general U.S. population?

Findings: This study, which analyzed fact sheets for three of the major U.S. vaccine manufacturers and other informational material, found that most of the COVID-19 vaccine-related informational materials did not meet appropriate readability levels for the U.S. population.

Meaning: Informational materials should be written at a 7th-grade reading level for the general population to fully comprehend them.



More than 130 million individuals in the United States have now received at least one dose of a COVID-19 vaccine. Currently, all adults in the Unites States now have access to one of three COVID-19 vaccines. As part of the vaccination procedure, Emergency Use Authorization (EUA) fact sheets, which contain information regarding the vaccine, are provided. The purpose of this study was to analyze the ease of reading (i.e., readability) of the EUA-approved fact sheets for the vaccines currently available in the United States, the V-Safe adverse event survey script, and the Centers for Disease Control and Prevention (CDC) website information on COVID-19 vaccines designed for the general public in the United States.


We acquired the Pfizer, Moderna, and Janssen EUA fact sheets, as well as the V-Safe survey script and the CDC website information regarding COVID-19 vaccines. These documents were analyzed for their complexity regarding the following readability factors: average length of paragraphs, sentences, and words; font size and style; use of passive voice; the Gunning-Fog index; the Flesch Reading Ease index; and the Flesch-Kincaid Grade Level index.


Only the V-Safe adverse-event survey script met readability standards for adequate comprehension. The mean readability scores of the EUA fact sheets and the CDC website were as follows: Flesch Reading Ease score (44.35 avg); Flesch-Kincaid Grade Level (10.48 avg); and Gunning-Fog index (11.8 avg). These scores indicate that at least a 10th-grade level education would be required to understand these reading materials.


The average person in the United States would have difficulty understanding the information provided in the EUA fact sheets and CDC COVID-19 vaccine website documents; however, the V-Safe survey was written at an adequate reading level. To ensure that the general public fully understands information regarding COVID-19 vaccines, greater care and effort should be given to the development of simplified information material.

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