Lessons from an online debate about measles-mumps-rubella (MMR) immunization

To provide strategies for immunization advocates on how best to participate in online discussion forums about immunization.

Content and thematic analysis of an online discussion forum held following the national screening of a documentary about the measles-mumps-rubella (MMR) vaccine and autism scare. A subsample of branches containing more than 20 posts was analysed. Each distinct message (a "post") was coded for the author's manifest position on immunization, author type, topic, and evidence presented or sought.

From 103 distinct branches there were 1193 posts sent over a 3½ h period. We selected the 13 longest branches containing 466 posts from 166 individuals. One third of these individuals were explicitly critical of MMR immunization and one third sought information. The remainder were ambivalent but seeking no information (5%), supportive (14%), or unstated (15%). Among five author categories, only 4% identified themselves as health professionals. Topics included alleged adverse effects of immunization (35%); autism spectrum disorders treatment and causes (31%); vaccine ingredients (12%); a conspiracy (9%); immunization policies (8%); and measles, mumps or rubella (4%). Scientific concepts of evidence failed to compete with lay concepts and personal anecdotes prevailed.

Health professionals and other advocates of immunization should engage in similar types of post-broadcast online discussion forums in a planned and strategic manner that accounts for the decision processes of lay people. This involves expanding and diversifying the support base of people contributing to the forum; setting the agenda; introducing messages known to influence behaviour; not overselling vaccination; and avoiding personal attacks.