Countering antivaccination attitudes

Abstract

Three times as many cases of measles were reported in the United States in 2014 as in 2013. The reemergence of measles has been linked to a dangerous trend: parents refusing vaccinations for their children. Efforts have been made to counter people's antivaccination attitudes by providing scientific evidence refuting vaccination myths, but these interventions have proven ineffective. This study shows that highlighting factual information about the dangers of communicable diseases can positively impact people's attitudes to vaccination. This method outperformed alternative interventions aimed at undercutting vaccination myths.

Keywords: attitude change; belief revision; science education; vaccination.

Fig. 1.

Vaccine attitude change scores across conditions (posttest − pretest). A one-way ANOVA revealed a significant difference between the three conditions [F(2,312) = 5.287, P = 0.006]. This effect was driven by the disease risk condition, which led to larger changes in vaccination attitudes than either the control [t(212) = 3.04, P = 0.003, d = 0.41, 95% highest density interval (HDI; a Bayesian estimate of the most credible values of the difference) (15) = 0.058, 0.292] or the autism correction condition [t(203) = 2.41, P = 0.017, d = 0.33, 95% HDI of the difference = 0.009, 0.269]. The effect of the autism correction condition was no greater than that observed in the control condition [t(209) = 0.358, P = 0.721, d = 0.05, 95% HDI of the difference = −0.066, 0.138].

Fig. 2.

Vaccine attitude change scores across conditions (posttest − pretest) divided into terciles based on pretest score. A 3 × 3 factorial ANOVA compared conditions among each tercile and revealed significant main effects of condition [F(2,306) = 5.362, P = 0.005, η² = 0.034] and tercile [F(2,306) = 32.10, P < 0.001, η² = 0.173]. A significant interaction was also observed between these two factors [F(4,306) = 3.735, P = 0.006, η² = 0.047], indicating that condition differences were greatest among participants in the bottom tercile. Change scores were significantly larger in the disease risk condition compared with the control condition among participants in the bottom [t(65) = 3.23, P = 0.002, d = 0.79, 95% highest density interval (HDI) of the difference = 0.126, 0.682] and middle [t(77) = 2.76, P = 0.007, d = 0.62, 95% HDI of the difference = 0.094, 0.473] terciles. Finally, in the top tercile, change scores were slightly negative for all three conditions, which might be expected because of both ceiling effects and regression to the mean. Change scores tended to be more negative for the disease risk condition than for the control condition, although this difference was not statistically significant [t(66) = −1.79, P = 0.077, d = 0.44, 95% HDI of the difference = −0.030, 0.020]. The weak regressive trend did not outweigh the overall positive effects of the disease risk intervention on vaccination attitudes for more skeptical participants.

Fig. 3.

Frequency of pretest vaccine attitudes.

Fig. 4.

Vaccine attitude change scores by condition for parents and nonparents.