What Makes Vaccine Information Trustworthy?

Using questions and answers retrieved from “Yahoo! Answers,” we explored how individuals seek vaccine information online and evaluate its trustworthiness in a series of studies.

Research Question

Are the following factors associated with the perceived trustworthiness of online content about vaccines?

  • The answer's stance towards vaccination (i.e., does it matter if the answer encourages or discourages vaccination?)
  • The answerer's self-identification (i.e., does it matter if the answer is written by someone who identifies as a health professional, as someone who identifies as a parent, or as someone who does not identify as either?)


We conducted an online experiment to find out if the stance of the answer and the identity of the answerer affects the perceived trustworthiness of the answer in online Q&A plaforms.

Participants were shown authentic answers that were either pro- or anti-vaccination and written by self-identified health professionals, by self-identified parents, or by answerers who did not identify as either.

Participants were then asked to rate the trustworthiness of the answerers, fill out an attention check, and indicate their agreement with four statements pertaining to vaccine confidence (e.g., "Overall I think vaccines are safe").

We then followed up with a moderation process analysis of the trustworthiness ratings:

Answerer's self-identification ---> Perceived epistemic trustworthiness
                                Answer's stance towards vaccination

Note: The statistical analyses for this part of the project were conducted by a freelance consultant, Dr. Amihai Rigbi. I designed the experiment, wrote up the findings and drew the figures.

Findings and Discussion

On average, the answerer's self-identification is associated with the trustworthiness ratings. However, that relationship is moderated by the answer's stance towards vaccination: It is stronger among answers that encourage vaccination than among answers that discourage it.

It seems that at least in this context, on average, experts are considered more trustworthy than parents. It is a small effect (compared to the answer's stance) but it still measurable, even among vaccine-hesitant raters.

Take-home message: Internet users consider both "what is said" and "who said it." Expert outreach in online environments has a small, but measurable effect. This type of outreach may help to address vaccine hesitancy.


Figure 1. Epistemic trustworthiness ratings by answer's stance towards vaccination and answerer self-identification.

(a) Descriptive statistics of trustworthiness ratings for all raters, for vaccine-hesitant raters, and for vaccine-confident raters. Ratings are based on the mean of 14 questionnaire items on a 7-point Likert scale. Error bars denote the standard error of the mean.

(b) Moderation analyses predicting epistemic trustworthiness ratings. These analyses examine whether different variables predict trustworthiness ratings, and if so, to what extent, and whether the relationship between answerer self-identification and trustworthiness depends on the answer's stance towards vaccines. One moderation analysis was performed for all raters, and one analysis each for vaccine-hesitant raters and vaccine-confident raters. Each independent variable was attributed a standardized regression coefficient (beta coefficient), which describes the extent to which changes in that variable are related to changes in trustworthiness ratings, when holding all other variables constant, where changes in variables are measured in standard deviations.

One, two and three bullets (•, ••, •••) denote significance at the 0.05, 0.01 and 0.001 levels, respectively.

Press Releases and Media Coverage

איך מעבירים מדע ברשת? - מכון דוידסון, 22.3.2020


Sharon, A. J., Yom-Tov, E., & Baram-Tsabari, A. (2020). Vaccine information seeking on social Q&A services. Vaccine, 38(12), 2691–2699. https://doi.org/10.1016/j.vaccine.2020.02.010