COVID-19 and Optimal Lockdown Strategies: The Effect of New and More Virulent Strains

Abstract

Most nations have responded to the COVID-19 pandemic by locking down parts of their economies starting in early 2020 to reduce the infectious spread. The optimal timing of the beginning and end of the lockdown, together with its intensity, is determined by the tradeoff between economic losses and improved health outcomes. These choices can be modelled within the framework of an optimal control model that recognises the nonlinear dynamics of epidemic spread and the increased risks when infection rates surge beyond the healthcare system’s capacity. Past work has shown that within such a framework very different strategies may be optimal ranging from short to long and even multiple lockdowns, and small changes in the valuation on preventing a premature death may lead to quite different strategies becoming optimal. There even exist parameter constellations for which two or more very different strategies can be optimal. Here we revisit those crucial questions with revised parameters reflecting the greater infectivity of variants such as the “UK variant” of the SARS-CoV-2 virus and describe how the new variant may affect levels of mortality and other outcomes.

Should the COVID-19 lockdown be relaxed or intensified in case a vaccine becomes available?

“…[11] includes the effect of social fatigue and endogenous treatment capabilities. [12][13][14] concentrate on the qualitative behavior of the solution and identify parameter regions where the optimal solution is qualitative stable. The parameter regions are separated by bifurcation curves where Skiba solutions or other interesting mathematical phenomena arise.…”

“…The death rate is increasing in I due to the congestion effects of the health sector (for dramatic examples we refer to Lombardia in Italy or New York City both in spring 2020, or Brazil in spring 2021). Several contributions use a similar form, see e.g., [12][13][14]…”

“…important. The government has the responsibility for the epidemic situation when elections take place (see e.g., [12,14], or [30]).…”

“…seems to be problematic. This so-called "lockdown fatigue" effect is thoroughly addressed in [13,14]. The analysis shows that the shape of the optimal lockdown over time need not be hump-shaped, but can have several peaks.…”

Decomposing the role of mobility restrictions in controlling COVID-19 outcomes: a regional level study of the Philippines

“…Balancing the health and economic trade-offs of NPIs is crucial in resolving pandemicrelated problems, and the optimal impact of NPIs and optimal lockdown strategies have been dissected by various scholars (Tildesley et al, 2021;Caulkins et al, 2022;Acemoglu et al, 2020). A study by Tildesley et al (2021) revealed that precision in timing and strength of interventions is highly determined by the control's target: instituting an optimal level of control can lead to a decrease in net monetary loss, conditional on the precise willingness to pay per quality adjusted life year value.…”