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. Moreover, the importance of some NPIs is likely to remain in the future, at least in specific settings, in which the limited vaccination coverage and the high rate of contacts would enable further disease transmission. Nonetheless, the benefits of NPIs have been questioned with respect to their effectiveness and societal costs. In this study of 28 European countries during the first wave of epidemic we demonstrate a significant inverse correlation between the stringency of adopted containment measures and cumulative incidences of the confirmed COVID-19 cases. Our results indicate that early implementation of the stringent containment measures prior to detection of the first confirmed case, and rapid ramp-up of containment stringency after the first case was diagnosed, were instrumental for lowering the number of COVID-19 cases during the epidemic wave. The impact of delayed adoption of containment measures could not be fully attenuated by later adoption of even more stringent community containment.