Total containment of population and number of confirmed cases of COVID-19 in England, Belgium, France and Italy

We analyse the impact of total population containment on the evolution of the growth rate of confirmed cases of coronavirus disease 2019 (COVID-19) by controlling the results by the situation observed in a country that has not applied this measure. We conducted a study of four European countries, England, Belgium, France and Italy, taking Sweden as a control country that did not confine its population. To do so, we use the interrupted time series method. Comparisons of the postintervention linear trends of COVID-19 confirmed cases from England, Belgium and France with that of Sweden show no statistically significant difference. Comparison of the postintervention linear trends of COVID-19 confirmed cases from Italy with that from Sweden shows a positive and statistically significant difference. It reflects a dynamic in the growth rate of confirmed cases in Italy higher than that observed in Sweden despite the total containment of the population. The results obtained therefore lead to the conclusion that the measure of total population containment is ineffective in the countries sampled. This suggests that the evolution of confirmed cases of COVID-19 could be the result of a combination of other factors and not specifically of total population containment.