Mandates without backlash: COVID-19 vaccine policies and the uptake of other vaccines

Abstract This paper examines whether mandatory COVID-19 vaccination policies generated spillover effects on the uptake of other vaccines. Using a global country-year panel, we combine COVID-19 vaccine mandate data from the Oxford COVID-19 Government Response Tracker with international vaccination coverage data for discretionary vaccines, including Human Papillomavirus (HPV) and Influenza, and routine childhood vaccines, including Measles-containing, Rubella-containing, Diphtheria-Tetanus-Pertussis (DTP)-containing, Polio-containing, Haemophilus influenzae type b (Hib)-containing, Hepatitis B-containing, Rotavirus-containing, and Pneumococcal-containing vaccines. The treatment is measured by a binary indicator that equals 1 if a country adopted any COVID-19 vaccine mandate. To address staggered mandate adoption and treatment effect heterogeneity across countries, we estimate dynamic average treatment effects for switching countries using the de Chaisemartin and D’Haultfoeuille (2026) staggered difference-in-differences estimator. Overall, we find no systematic evidence of declines in national coverage rates for other vaccines following COVID-19 vaccine mandate adoption. This is true for almost all vaccines studied. However, for some routine childhood vaccines, evidence of differential pre-treatment trends warrants caution in interpreting those estimates as definitive evidence of no causal effect. Power and sensitivity analyses show that, for seven routine outcomes, first-period declines can be excluded under moderate departures from parallel trends.