The stringency of the containment measures in response to COVID-19 inversely correlates with the overall disease occurrence over the epidemic wave.

Non-pharmaceutical interventions (NPIs) were the only viable choice to mitigate or suppress transmission of COVID-19 in the absence of efficient 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 first 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 first confirmed 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 significant 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). Keywords: non-pharmaceutical interventions, containment, COVID-19, mobility, social distancing, Containment and Health Index, epidemiology, public health measures, SARS-CoV-2.