News media framing of vaccination uptake and herd immunity: A content analysis

Abstract

Background: The media can frame vaccination uptake negatively (e.g., as “low” or “poor”), appealing to fear to motivate people to get vaccinated. However, according to the descriptive norms theory, this could backfire. Public communication should instead highlight positive static (“most people are vaccinated”) or dynamic norms (“more and more people are getting vaccinated”). Additionally, communicating herd immunity (if enough people have immunity through vaccination, the virus is contained) could signal the importance of high vaccination uptake. Methods: We conducted a quantitative content analysis of all articles on vaccines and vaccination (N=160) published between July 1 and December 31, 2017 (during the measles outbreak) by nine highest-trafficked news websites in Serbia. Findings: Half of the articles (53.75%) included vaccination rates, mentioning them 339 times. Vaccination rates were usually on a country- (41.30%) or city-level (31.56%) and sourced from national/local health experts and organizations (64.31%). Rates communicated both static (71.09%) and dynamic (28.91%) norms, which were negatively framed 72.61% and 68.37% of the time, respectively. The numerical value of the vaccination rate was not provided in 42.18% of the cases. Out of the 32 articles mentioning the term “herd/collective immunity”, 11 gave the full definition of this effect. The critical immunity threshold (e.g., 90-95% for measles) was provided in 37 articles. Discussion: To report effectively and ethically, the Serbian online news media should focus readers’ attention on positive trends in vaccination and provide precise vaccination rate values. Information on vaccination uptake should be accompanied with an explanation of herd immunity through vaccination.