Non-pharmaceutical interventions (NPIs) were the only viable choice to mitigate or suppress transmission of COVID-19 in the absence of effi cient and safe vaccines. In this study, we examined the association between the stringency of containment measures and cumulative incidence of the COVID-19 cases in the fi rst wave of the pandemic across 28 European countries. Our results support the effectiveness of containment measures in the mitigation or suppression of COVID-19 epidemics. Early adoption of stringent containment measures prior to detection of the fi rst confi rmed case, together with ramping up containment stringency during the early days of epidemics, was associated with a lower disease occurrence. The delayed adoption of stringent containment measures did not fully compensate for the lack of early response. Containment measures continue to play a signifi cant role in the control of COVID-19 in the post-vaccination period, when limited vaccination coverage, the emergence of vaccine resistance, and/or increased mobility enabled further disease transmission (Tab. 4, Fig. 22, Ref. 50).