Zero-sum or worse? Considering detrimental effects of selective mandates on voluntary childhood vaccinations

To the Editor:

Savulescu et al argued that mandating vaccination of children against coronavirus disease 2019 (COVID-19) could contribute to public health but may be difficult to justify, given the low disease severity and uncertainties about vaccination safety and effectiveness for children.¹ However, when assessing the utility of mandatory vaccination, potential detrimental effects on the uptake of voluntary vaccines should also be considered. Based on reactance theory and previous research,2, 3, 4 we expected that mandating children’s vaccinations against COVID-19 could elicit parental anger and motivate the refusal of voluntary vaccines. To test our assumption, we conducted an online experiment on May 18 and 19, 2021, as part of a larger study with 950 German participants, quota-representative for age × sex and federal state. A subset of 244 participants were parents of children under 18 years of age and, thus, enrolled in the experiment. They were 18-70 years old (mean = 38.86, SD = 9.72), 119 were male and 125 female. After assessing their attitudes toward mandatory vaccination (31% supported a mandate for children), one-half of the participants should imagine that vaccinating their children against COVID-19 would be recommended, but voluntary; the remainder should imagine mandatory vaccination. All parents were asked how angry they felt about the imagined regulation. Afterward, they read a short text about meningococcus type B and were asked to imagine that vaccination against this disease was recommended (which was not the case in reality) but voluntary for their children. Finally, they indicated how likely they would be to get their children vaccinated against meningococcus type B. A mandatory vaccination policy elicited anger in parents, especially when support for a mandate was low (Figure A , solid line). For these parents, meningococcus vaccination intentions were also lower compared with parents who were offered a voluntary vaccination (Figure B). As the results were drawn from hypothetical decisions, the detrimental effects of mandatory regulations on the overall vaccination program may be even stronger in reality. Therefore, decision-makers should focus on other measures, such as communication interventions addressing concerns about vaccine safety and efficacy and highlighting the benefits of children’s vaccination for the protection of vulnerable populations.^{5 , 6}

Figure.

Effects of voluntary and mandatory vaccination of children against COVID-19. Results from linear regression analyses; ribbons visualize 95% CIs. A, Imagining mandatory vs voluntary COVID-19 vaccination for children elicited anger in their parents (β = 0.41, b = 1.81, SE = 0.19, 95% CI [1.43; 2.18]), especially when support for a mandate was low (interaction effect: β = −0.88, b = −1.19, SE = 0.09, 95% CI [−1.35; -1.02]). B, In this case, intentions to get children vaccinated against meningococcus type B were also lower (interaction effect of mandatory vs voluntary vaccination and support for mandatory vaccination: β = 0.28, b = 0.33, SE = 0.10, 95% CI [0.12; 0.53]).