DP14852 Waning Immunity and the Second Wave: Some Projections for SARS-CoV-2

Author(s): Chryssi Giannitsarou, Stephen Kissler, Flavio Toxvaerd
Publication Date: June 2020
Date Revised: April 2021
Keyword(s): COVID-19, Economic epidemiology, optimal policy for infection control, SEIRS, Social distancing, waning immunity
JEL(s): E61, I18
Programme Areas: Public Economics, Macroeconomics and Growth
Link to this Page: cepr.org/active/publications/discussion_papers/dp.php?dpno=14852

This paper offers projections of future transmission dynamics for SARS-CoV-2 in an SEIRS model with demographics and waning immunity. In a stylized optimal control setting calibrated to the USA, we show that the disease is endemic in steady state and that its dynamics are characterized by damped oscillations. The magnitude of the oscillations depends on how fast immunity wanes. The optimal social distancing policy both curbs peak prevalence and postpones the infection waves relative to the uncontrolled dynamics. Last, we perform sensitivity analysis with respect to the duration of immunity, the infection fatality rate and the planning horizon.