ABSTRACT
BACKGROUND: Governments around the world used mobile vaccination units (MVUs) to increase COVID-19 vaccine uptake, but the causal effect of MVUs has not yet been evaluated. METHODS: In a randomized controlled trial (RCT) with 20 Swiss communities (10 treatment, 10 control) in August 2021, MVUs were sent to treatment communities for 4 hours on a single day. The experimental sample comprises 20 414 adults who were unvaccinated against COVID-19 at this point. The researchers designed the RCT and the government introduced the idea to test the effectiveness of MVUs and was responsible for administering the vaccines. RESULTS: The vaccination rate in the sample of the treatment group surpassed the rate in the control group by a factor of 3.4 (+9.0 percentage points) over 3 weeks. The increase was present and highly statistically significant for women, men and for all age groups. We found no evidence of cannibalization of vaccinations at other service locations. CONCLUSIONS: The offer of MVUs is highly effective in raising vaccination rates, even at a later point in the vaccination campaign. The absence of cannibalization effects suggests that MVUs reach more people overall, not just faster.
