Effects of national containment measures on decelerating the increase in daily new cases of COVID-19 in 54 countries and four epicenters of pandemic.

BACKGROUND: COVID-19 presents a worldwide epidemic, and various countries have responded differently in terms of containment measures to reduce disease transmission, including stay-at-home orders, curfews and lockdowns. Comparative studies are yet to be conducted to investigate the impact of these containment measures, which would be needed to facilitate public health policy-making across countries.

OBJECTIVE: To describe and evaluate the effects of national containment measures and policies (stay-at-home orders, curfews and lockdowns) on decelerating the increase in daily new cases (DNC) of COVID-19 in 54 countries and four epicenters of pandemic in different jurisdictions around the world.

METHODS: We reviewed the effective dates of national containment measures (stay-at-home order, curfew, or lockdown) of 54 countries and four epicenters of coronavirus pandemic (Wuhan, New York, Lombardy, and Madrid), and searched cumulative numbers of COVID-19 confirmed cases and DNC from health authorities. Data were drawn from an open, crowdsourced, daily updated COVID-19 dataset from covid.ourworldindata.org hosted by Our World in Data. We examined the trends in the % increase in DNC from 7 days before to 30 days after the effective dates of measures by continents, World Bank income classification, types of containment measure, effective dates of containment measures, sizes of confirmed cases at effective date of containment measures.

RESULTS: We included 122,366 patients with confirmed COVID-19 infection from 54 countries, and 24,071 patients from four epicenters on the effective dates of containment measures where stay-at-home orders, curfews, or lockdowns took place between 23rd January and 11st April 2020. Stay-at-home, curfew, and lockdown were commonly commenced for countries with around 30%, 20%, and 10% increase in DNC, respectively. All three measures were found to lower the % increase in DNC to <5% within one month. 40.7% of countries had an average % increase in DNC of ≥50% over seven days prior to the commencement of containment measures, where the % increase in DNC was curbed to 10% and 5% in at most 18 days and 26 days after the implementation of containment measures, respectively.

CONCLUSIONS: Different national containment measures were associated with a decrease in the DNC confirmed with COVID-19 infection. Stay-at-home orders, curfews and lockdowns curbed the % increase in DNC to <5% within a month. Resurgence in cases within one month was observed in some South American countries.