Comparison of engagement gained by vaccine-related content from source set Q to source set R (external comparison).

Denoted with <i>X</i> the vaccine subject, Table shows the results of Mann-Whitney U test applied to the distributions of the out-engage factor <i>P</i>(<i>Q</i>,<i>R</i>;<i>X</i>;<i>d</i>) for the days <i>d</i> when it is in favor of source set Q and source set R, respectively. Since the distributions have values of opposite sign (See Eq (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0316258#pone.0316258.e029" target="_blank">4</a>) in the main text), the test is applied to the distributions of absolute values. Distributions are compared according to the period analyzed: Overall (1 January 2016–31 December 2021), pre-pandemic (1 January 2016–29 January 2020) and pandemic (30 January 2020–31 December 2021). (DOCX)